Hi Andrew,
sorry for the very late response.
It would be best if you could provide a pcap file that contains the relevant interfaces (at least Abis + A, i.e. tcp port 3002 + 3003 and all sctp traffic, as well as udp port 2727), and enable logging to gsmtap on the relevant network elements (osmo-bts + osmo-bsc).
This way a single file contains all of the log output and the signalling in one timeline, and one is able to easily filter log verbosity / subsystems in the wireshark dissector for gsmtap_log.
Also, DTRX DEBUG should really be avoided, unless you are debugging something low level on the TRX<->BTS interface. It spans the logs and increases the CPU usage quite a bit, which might cause new troubles...
In fact, I only see DTRX, DL1P and DL1C in the osmo-bts logs (all related to TRX interface) but not the more relevant sub-systems that handle the RSL / RR / Abis side of things.