Restarting a level with 20+ moving entities halves FPS

I have been working on constructing my new level Gambit, which uses a large number of moving entities, so I have gotten to experience one of their biggest bugs firsthand. Once I got above about 20 moving entities, the game started lagging considerably when I would restart the level, halving FPS for each time the level was restarted. Closing the level and reopening it fixed the problem, but it is still irritating to have to go through that process. I don't know what specifically causes it, but something seriously reduces fps simply for restarting the level.

Note that I use Windows 8.1, in case OS affects anything.

Known issue, was fixed on development build and will be pushed at some point to public.