I raised an issue as well, hope github is the right place for this.
Details are also reported below:
In some cases, when something goes wrong during the compiling procedure, the editor crashes and the compiler gets stuck in the middle of something.
This behaviour occurs, for instance, when you have typos in SFC transitions (e.g. a ANDb instead of a AND b). The returned windows error is "file \xe8 is already used by another process".
Not sure this report helps, but it may be something worth checking (the only fix I find is to reboot the system, which may be very annoying when you are trying to track down the bug).