I apologize but I mis-spoke earlier.
The change I noticed a while back was a modification of the "volume" naming convention for the par2 files containing repair blocks... part of which was a change from a plus "+" sign to a minus "-" sign. But those sets still contain a "small" par2 file with no volume info. And those par sets do still pause the recovery files properly in Alt.Binz. According to the MultiPar GUI, this format that I have been seeing for a while now is generated by the program ParPar (
https://github.com/animetosho/ParPar).
This other par naming format (that doesn't pause the recovery files) also uses the minus "-" symbol instead of plus "+" but all files have "vol" in the name (even the small par2). At first I thought this was something new, but now I think it is something old. So far I have only seen this on nzbs I have grabbed from nzbgeek (but I will keep checking around). The oldest example I found was something I downloaded from nzbgeek in 2022, but the actual usenet post was uploaded in 2011!!! According to MultiPar, those 2011 par files were created by the program par2cmdline v 0.4 (
https://github.com/Parchive/par2cmdline). The similar ones I grabbed from nzbgeek yesterday (for a new release less than 2 days old and shown in the previous screenshots) were created with par2cmdline v 0.8.1. That seems to be the newest version of par2cmdline from 2020.