You should be able to tell from chip order and nonce range affected.

If it works as planned then bank 0 (U6...) should have it's high bit = 0, and bank 1 (U9...) should have it's high bit = 1. One thing I'm not certain about is when pushed if they get picked up in order or reverse order by the chain. Some testing on that should tell. I could tell my board I have 8 chips and then see which 4 don't get any hashes.

So in the stats chips 0-7 should be U6, U8, U5, U7, U2, U4, U1, U3
and chips 8-15 should be starting from U9, U11, U10, U12, U13, U15, U14, U16

So in theory your problem chips are U6, U8 and U12.
But if reverse order then would be U3, U1 and U13.

Testing with a lower chip count ought to show but I haven't thought about the right way to prime the ranges.