Hey,
This crash appears to happen only when you attempt to run netprofile on multiple instances simultaneously. This has been fixed for 4.9 so that each instance will write to a different .tmp file. I was also only able to reproduce issue with a .tmp file not converting over to a .nprof file after this crash occurred. If you’re able to reproduce that issue again in a different circumstance, please let us know. Until 4.9, to avoid this client crash, you’ll need to make sure you’re only running netprofile on one instance of game at a time.
Hope that helps!