I don't think it's related either, I get it too.
You can close the project, but Construct does not exit, and the close button doesn't do anything.
You can however load projects. But at that point I didn't trust it would be safe to save them again, and shut it down with the task manager.
Happened at least twice so far, maybe more, it was so inconsistent, I didn't bother committing them to memory.
Unknown on session length, as I keep it running for days.