So after running ufonormalizer on the files things seem to work. It takes a really long time to compile (about 10 minutes, though that drops to about 1 or 2 minutes if I turn off autohinting), but it does work. I'm not sure what ufonormalizer actually changed (it looks the same to me) but nothing crashes and there is a working OTF at the end of the process.
thanks and sorry!
my post was missing all the info.
it happened yesterday for the first time. robofont crashed when i wanted to safe a ufo.
at the moment of the crash there also was a script open in the drawbot extension.
and when I reopened robofont it also opened the script but in the robofont editor.
guess that caused the confusion.