Today I learned that you can totally just call Kenwood support and get it while you wait on the line. The firmware and the flashing program. Took like 5min.
Didn't fix the problem though.
Coming to the party a little late, you state the problem did not get corrected.
(this may be a rehash / refresher for most of you, sorry.)
One question remains not answered, what is the repeater model. Not that it makes or breaks the thread, but I'd be interested also.
Thinking out loud, some people goes as far as OFFSET RAN CODES in ENCODE and DECODE. So the question remains, what repeater is being used.
NXR-810, does not have esn validation. Only in a trunked system can this be used. HOWEVER!!!!!
You can have UID List OR Group ID list for a tighter anchor chain, when it is networked.
NOTE: This only works with a networked multi-site function, as I have tested it locally and radio traffic still passes locally.
The NXR-1000 is GUI based, and I do not have one on my desk to screenshot it for reference.
NOW the meat of this post.
NX1300, 3300, and my 5300, all communicate simplex every which way I could thing of except 1 item, audio settings.
Just to clarify, nx3300 talks but 1300 does not hear from it, but green light shows.

Are you seeing ANYTHING remotely similar to the above photo?
Optional Signaling, Ran, or RAN & OPT Signal?
NX-3xXX
I will check back later on and see what you have
@oniell121