I found two more posts talking about memory leaks, and even PeterNLewis chimed in in them:
If all my macros are disabled, and I don't use the editor, the Engine stays low around 44 MB. But if I use the editor for an hour, like I was doing today helping people on the forums, the memory climbs, and right now it's over 1 GB. That's not enough to halt my system, but after another hour or two it will be at 3GB and I'll notice my system dragging down so I will restart the engine by then.
The funny thing is, there are only two macros active in my KM right now. I have every group disabled, except for the one macro I'm using to test things to help people on this forum, and one macro that maps F12 to "Cancel all macros" which I consider essential in case I end up with a macro in an infinite loop while it's grabbing my mouse and I otherwise lose control of my computer.