Good day JJ.
TNG translate what it gets from the PABX in this case it receive "incoming" from trunk PSTN0 and translate to "incoming". while on other trunks it receive the CLI and print the received CLI
Can compare the configuration of Trunk PSTN0 with PSTN1 trunk configurations.
take screenshots and also attach logs for PSTN0 and PSTN1
we don't do PABX support but will try to assist our level best
Regards
Luanda