Level doors problem

[Froge]

For some reason when I enter a particular map, the level door behind me (which will take me back to the previous map) doesn't respond. There won't be the door symbol or the text showing the name of the map the door leads to. It's as if the level door is just a static object. If I hug the door real close, I will briefly see the door symbol but it'll disappear immediately.

Strangely enough, if I throw a crate at the door, the door totally works fine again (door symbol and map name text is there, and I can access it). What?

Here are the coordinates of the door relative to the door frame:

Door frame:

X: -34.75
Y: 0
Z: 11

Door:

X: -34.74
Y: 0.08
Z: 11

Everything regarding the door is fine, including startpos, text entry, and map loaded. No other property has been changed.

Edit: The coding is not part of the problem. I completely deleted my .hps file related to this map and the problem with the level door still persists.

Edit 2: Might be related, but whenever I check "create on surface" when dragging in entities for just this map, HPL2 lags really bad for no reason. In every other map there is absolutely no lag. There is also no lag in this specific map if "En" beside "create on surface" is not checked.