newsbin.com

It appears that Newsbin recently started to rename the downloaded PAR2 files?

For example in a set with a RAR files ABC.part1.RAR etc, the downloaded PAR2 files would be renamed to something like ABC.857FF46E.PAR2 ; ABC.857FF46E.vol000+01.PAR2 etc

Is that correct? If so, why?
(I wonder if this may be related to some recent problems that I am having)

It's not recent and yes.

Because some morons post different file sets but use the same names for the PARS so, if you mix them in the same folder you'll have problems.