It does not matter if that object exists or not, I already tried to delete my local storage with the mozilla dev tools. But it does not fix it.

I can add new ones, but never delete old ones, unless i clear local storage.

Did anyone found a fix for this?

I have the same problem. In the steam client or in chromium it is working fine.

Firefox 49.0 on Xubuntu 16.04

I can confirm this, i also ran into this. I'm getting "Error: look coords are out of bounds" with lookForAtArea() on room edges.