We've been using nRF51822-QFAB-C0 for a few years without any problems. It is being used for rf comms with Gazell (S110 8.0.0 and SDK10.0.0)
If the software is put in the QFAB-A0 it appears to run until a transmit occurs in Gazelle. The timer interrupt is still running as I can toggle a gpio pin.
I've added a 12K pulldown to swdio/reset as required for this rev of IC.
Any ideas?