I have attached a .pcap file showing a location update
and then an originated call.
As suspected CCCH-CONF is 6, so it uses other timeslots than 0 for
paging and which time slots is used for your SIM depends on a formula
and the IMSI, you can't just select it. Currently osmocom-bb only
support timeslot 0, so you're out of luck there, you'll need to add
support for it yourself if you want to use it.
Cheers,
Sylvain