I’ve seen this mentioned before, so I did some searching, and here is the best explanation I could find:
This might have been a different parameter number — firmwre upgrades have added a couple that I can remember — but the outcome in all cases is that the value does not seem to be “initialized,” so might be random or even invalid, causing unexpected results. The best course of action as an end user is to explicitly configure new parameter values to something if the release notes indicate that one was added.
Whether this is something the firmware itself can do is another story; theoretically yes, given what Eric said, but whether they have space on already-jam-packed 500-series they’re using is probably a consideration.