Building Obstacles during runtime

Edit: I found a bug while trying to figure this out - trying to add backdrops as obstacles on Layer 1 does not work. It adds the backdrop, but does not detect them as obstacles.

My current app I'm working on is a game that will include many levels, which I would like to be able to load in at runtime to lower the file size. I have a loader working perfectly, but when the objects and backdrops complete loading in, the frame rate drops considerably (15-30 fps). If I put these same objects into the Frame Editor so the level is pre-loaded, the frame rate is a steady 45-50.

After toying around with my events, I've found that Pasting Objects Into Background (or Adding Backdrop) as an Obstacle or Platform is what is slowing down the game. If I paste as a Ladder or Not An Obstacle or No Effect On Collisions, it does not affect frame rate.

Tldr: It seems that building the background collision map during runtime (pasting/adding obstacles) significantly slows down the frame rate.

Anything I/we can do to fix this?

Can anyone confirm that creating obstacle backdrops during runtime lowers fps? Or that creating obstacles does not work on layer 1?