We have a cluster, running Octopus 15.2.2, with the same exact issue described
originally.
Confirmed, setting debug_rgw logs to "20/1" fixed the issue for us as well.
What information would be needed to begin a preliminary bug report? As with others, I
haven't found a way to easily replicate this issue. I can confirm this issue was also
not occasional for us, but also affected every bucket, always, like Stefan saw.