You can see the number of running functions in the F11 panel. If this number permanently increases, then the bug is a repeated call to a function containing a wait() somewhere in your code. Should be easy to find.
If the number of entities permanently increases, then the reason is a repeated ent_create call. The +1KB increase that you describe in your thread is possibly an entity creation because their size is just 1 KB.
If it's none of both, but the "mem" value increases permanently, then it's another create function of an engine object, f.i. of a panel, bitmap, material, sound or the like.