rsync suddenly showing strange behavior on OSX 15.5 (24F74)

[JJHelly]

Aloha. I've been using rsync for backup for decades. Recently, my standard backup scripts started throwing warnings like the following:

rsync(82180): warning: zero-length name in identifier list

And not just a few. I have no idea what this is and searching for it doesn't produce anything useful. I will scan the code for 82180 but I don't expect to understand what's going on from that unless I'm unusually lucky.

Any insight into what is causing, or even what it is, would be very helpful.
Mahalo.
J. Helly