1. I could only repro this when back end did not respond to return license request
2. in one session in unity I attempted to return license 3-4 times and waited for them to time out with the message saying "trying to connect"
3. playing around in unity after closing the return license window for a minute or two
4. go to manage license and select 'return license'
5. Unity closes but behave as if it crashes with crash bug-reporter appearing

Note: license is returned properly