Have you got objects correctly placed in your layouts? The way memory management works is it expects all objects that will be used on a layout to be placed on that layout in the editor. Then if you don't want them to be used on startup, add an event to destroy them on start of layout. This informs both the way objects are grouped on to spritesheets, and which objects are loaded in to memory at runtime when switching layouts.
Also if you switch the spritesheet size down to 512, then even if that same problem happens, it's only 1/4 as bad.