update: found out that this is a call manager issue. the CUCM traces show that the same configured third party sip phone is being returned as the destination for some bizarre reason and hence the user ...
Both endpoints can register on their own and we can see the password being correct in the traces. I suppose proof is that they can both register on their own
if Upper & Through is enabled only the first phone shows registered under "registered clients" in brekeke. It also shows registered in call manager (as expected with brekeke's IP Address ...
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