I wanted to share something that we've reported as a potential defect recently.
Whilst we don't have statistics, we suspect it could occur in older versions of Clarity but have had it reported prominently in version 14.2, and concerns itself with multiple process instances getting launched against the same object instance record after a single XOG/UI update - specifically when that process contains system actions which also set attributes on the object instance.
If you have or are considering process definitions with this design, my recent posting may be worth checking:
We've only had one actual case of this diagnosed with this result so far, but I suspect that has more to do with us not previously determining this as a root cause for it, and the problem has likely occurred a number of times before too. Even one case is not good though, as that one ended up with >3 million process instances being spawned in a short time frame, so prevention is certainly better than the cure.