Hi Nirfrash,
I think system behaviour is correct.
Please refer notes 160884, 529634 and 616732.
Meanwhile, you can also check OPTS tcode. Just check the system status is REL or not. If yes, then it is quiet obvious that whenever Project/WBS is released then system will definitely creates a new version and if you do not want system to create version, then you need to change the setting in OPTS.
But I suggest you to go with above mentioned OSS notes.
Regards,
Amit Rajoria