diff --git a/src/module.c b/src/module.c
index 034105d3e..cc6934dca 100644
--- a/src/module.c
+++ b/src/module.c
@@ -339,6 +339,7 @@ typedef struct RedisModuleDictIter {
 
 typedef struct RedisModuleCommandFilterCtx {
     RedisModuleString **argv;
+    int argv_len;
     int argc;
 } RedisModuleCommandFilterCtx;
 
@@ -10078,6 +10079,7 @@ void moduleCallCommandFilters(client *c) {
 
     RedisModuleCommandFilterCtx filter = {
         .argv = c->argv,
+        .argv_len = c->argv_len,
         .argc = c->argc
     };
 
@@ -10094,6 +10096,7 @@ void moduleCallCommandFilters(client *c) {
     }
 
     c->argv = filter.argv;
+    c->argv_len = filter.argv_len;
     c->argc = filter.argc;
 }
 
@@ -10125,7 +10128,10 @@ int RM_CommandFilterArgInsert(RedisModuleCommandFilterCtx *fctx, int pos, RedisM
 
     if (pos < 0 || pos > fctx->argc) return REDISMODULE_ERR;
 
-    fctx->argv = zrealloc(fctx->argv, (fctx->argc+1)*sizeof(RedisModuleString *));
+    if (fctx->argv_len < fctx->argc+1) {
+        fctx->argv_len = fctx->argc+1;
+        fctx->argv = zrealloc(fctx->argv, fctx->argv_len*sizeof(RedisModuleString *));
+    }
     for (i = fctx->argc; i > pos; i--) {
         fctx->argv[i] = fctx->argv[i-1];
     }
diff --git a/src/script_lua.c b/src/script_lua.c
index c86cdc2d1..365a41fb5 100644
--- a/src/script_lua.c
+++ b/src/script_lua.c
@@ -783,7 +783,7 @@ static void luaReplyToRedisReply(client *c, client* script_client, lua_State *lu
 /* ---------------------------------------------------------------------------
  * Lua redis.* functions implementations.
  * ------------------------------------------------------------------------- */
-void freeLuaRedisArgv(robj **argv, int argc);
+void freeLuaRedisArgv(robj **argv, int argc, int argv_len);
 
 /* Cached argv array across calls. */
 static robj **lua_argv = NULL;
@@ -795,7 +795,7 @@ static int lua_argv_size = 0;
 static robj *lua_args_cached_objects[LUA_CMD_OBJCACHE_SIZE];
 static size_t lua_args_cached_objects_len[LUA_CMD_OBJCACHE_SIZE];
 
-static robj **luaArgsToRedisArgv(lua_State *lua, int *argc) {
+static robj **luaArgsToRedisArgv(lua_State *lua, int *argc, int *argv_len) {
     int j;
     /* Require at least one argument */
     *argc = lua_gettop(lua);
@@ -809,6 +809,7 @@ static robj **luaArgsToRedisArgv(lua_State *lua, int *argc) {
         lua_argv = zrealloc(lua_argv,sizeof(robj*)* *argc);
         lua_argv_size = *argc;
     }
+    *argv_len = lua_argv_size;
 
     for (j = 0; j < *argc; j++) {
         char *obj_s;
@@ -848,7 +849,7 @@ static robj **luaArgsToRedisArgv(lua_State *lua, int *argc) {
      * is not a string or an integer (lua_isstring() return true for
      * integers as well). */
     if (j != *argc) {
-        freeLuaRedisArgv(lua_argv, j);
+        freeLuaRedisArgv(lua_argv, j, lua_argv_size);
         luaPushError(lua, "Lua redis lib command arguments must be strings or integers");
         return NULL;
     }
@@ -856,7 +857,7 @@ static robj **luaArgsToRedisArgv(lua_State *lua, int *argc) {
     return lua_argv;
 }
 
-void freeLuaRedisArgv(robj **argv, int argc) {
+void freeLuaRedisArgv(robj **argv, int argc, int argv_len) {
     int j;
     for (j = 0; j < argc; j++) {
         robj *o = argv[j];
@@ -878,7 +879,7 @@ void freeLuaRedisArgv(robj **argv, int argc) {
             decrRefCount(o);
         }
     }
-    if (argv != lua_argv) {
+    if (argv != lua_argv || argv_len != lua_argv_size) {
         /* The command changed argv, scrap the cache and start over. */
         zfree(argv);
         lua_argv = NULL;
@@ -894,8 +895,7 @@ static int luaRedisGenericCommand(lua_State *lua, int raise_error) {
     client* c = rctx->c;
     sds reply;
 
-    c->argv = luaArgsToRedisArgv(lua, &c->argc);
-    c->argv_len = lua_argv_size;
+    c->argv = luaArgsToRedisArgv(lua, &c->argc, &c->argv_len);
     if (c->argv == NULL) {
         return raise_error ? luaError(lua) : 1;
     }
@@ -977,7 +977,7 @@ static int luaRedisGenericCommand(lua_State *lua, int raise_error) {
 cleanup:
     /* Clean up. Command code may have changed argv/argc so we use the
      * argv/argc of the client instead of the local variables. */
-    freeLuaRedisArgv(c->argv, c->argc);
+    freeLuaRedisArgv(c->argv, c->argc, c->argv_len);
     c->argc = c->argv_len = 0;
     c->user = NULL;
     c->argv = NULL;
@@ -1128,8 +1128,8 @@ static int luaRedisAclCheckCmdPermissionsCommand(lua_State *lua) {
     serverAssert(rctx); /* Only supported inside script invocation */
     int raise_error = 0;
 
-    int argc;
-    robj **argv = luaArgsToRedisArgv(lua, &argc);
+    int argc, argv_len;
+    robj **argv = luaArgsToRedisArgv(lua, &argc, &argv_len);
 
     /* Require at least one argument */
     if (argv == NULL) return luaError(lua);
@@ -1148,7 +1148,7 @@ static int luaRedisAclCheckCmdPermissionsCommand(lua_State *lua) {
         }
     }
 
-    freeLuaRedisArgv(argv, argc);
+    freeLuaRedisArgv(argv, argc, argv_len);
     if (raise_error)
         return luaError(lua);
     else
diff --git a/tests/unit/moduleapi/commandfilter.tcl b/tests/unit/moduleapi/commandfilter.tcl
index 723dd1409..427609d3e 100644
--- a/tests/unit/moduleapi/commandfilter.tcl
+++ b/tests/unit/moduleapi/commandfilter.tcl
@@ -96,3 +96,23 @@ start_server {tags {"modules"}} {
         assert_equal {OK} [r module unload commandfilter]
     }
 } 
+
+test {RM_CommandFilterArgInsert and script argv caching} {
+    # coverage for scripts calling commands that expand the argv array
+    # an attempt to add coverage for a possible bug in luaArgsToRedisArgv
+    # this test needs a fresh server so that lua_argv_size is 0.
+    # glibc realloc can return the same pointer even when the size changes
+    # still this test isn't able to trigger the issue, but we keep it anyway.
+    start_server {tags {"modules"}} {
+        r module load $testmodule log-key 0
+        r del mylist
+        # command with 6 args
+        r eval {redis.call('rpush', KEYS[1], 'elem1', 'elem2', 'elem3', 'elem4')} 1 mylist
+        # command with 3 args that is changed to 4
+        r eval {redis.call('rpush', KEYS[1], '@insertafter')} 1 mylist
+        # command with 6 args again
+        r eval {redis.call('rpush', KEYS[1], 'elem1', 'elem2', 'elem3', 'elem4')} 1 mylist
+        assert_equal [r lrange mylist 0 -1] {elem1 elem2 elem3 elem4 @insertafter --inserted-after-- elem1 elem2 elem3 elem4}
+    }
+}
+
diff --git a/tests/unit/scripting.tcl b/tests/unit/scripting.tcl
index fa617d7fe..440b9e2e1 100644
--- a/tests/unit/scripting.tcl
+++ b/tests/unit/scripting.tcl
@@ -585,6 +585,30 @@ start_server {tags {"scripting"}} {
         close_replication_stream $repl
     } {} {needs:repl}
 
+    test {INCRBYFLOAT: We can call scripts expanding client->argv from Lua} {
+        # coverage for scripts calling commands that expand the argv array
+        # an attempt to add coverage for a possible bug in luaArgsToRedisArgv
+        # this test needs a fresh server so that lua_argv_size is 0.
+        # glibc realloc can return the same pointer even when the size changes
+        # still this test isn't able to trigger the issue, but we keep it anyway.
+        start_server {tags {"scripting"}} {
+            set repl [attach_to_replication_stream]
+            # a command with 5 argsument
+            r eval {redis.call('hmget', KEYS[1], 1, 2, 3)} 1 key
+            # then a command with 3 that is replicated as one with 4
+            r eval {redis.call('incrbyfloat', KEYS[1], 1)} 1 key
+            # then a command with 4 args
+            r eval {redis.call('set', KEYS[1], '1', 'KEEPTTL')} 1 key
+
+            assert_replication_stream $repl {
+                {select *}
+                {set key 1 KEEPTTL}
+                {set key 1 KEEPTTL}
+            }
+            close_replication_stream $repl
+        }
+    } {} {needs:repl}
+
     } ;# is_eval
 
     test {Call Redis command with many args from Lua (issue #1764)} {