Yes, I've seen this. The more time you spend in layouts, modifying things, the slower FMPA gets. You need to restart every couple of hours at least. Similar specs.
Thank you for your post.
Can you describe your layout in a bit more detail. That is, how many objects are on the layout? What type of objects are on the layout (e.g., 10 text fields, 2 portals, 1 merge field, 1 Container field, 1 Web Viewer, etc. - or post a screen shot)? Any other information you can provide may provide a key into what is causing the memory leak.