Bug: Remove Overlap on X produces unexpected result

I experienced an unexpected behaviour of the Remove Overlap function both as the Filter and on Export for the letter X.

[imgs=http://img838.imageshack.us/img838/416/removeoverlapbug.jpg][/imgs]

The strange thing is it sometimes works in other Masters but haven’t found out what makes it work.

(For now I can work around this by not making it a “full” Overlap.)

This is a problem with an Adobe technology Glyphs uses internally. The only workaround currently is to add an extra point on the path that disappears.