We have large glitches when we switch the coil driver state for PRM in every example that I've looked at. This causes locklosses, about 5 over the weekend.
One thing that we can do to make this less painfull is to move the switch earlier in the locking process (for example, we can try doing this right after DRMI locks rather than waiting until DRMI on POP).
A real solution might be to change the front end model so that we can switch each coil separately.
We could try tuning the delay, as described for the LLO BS 16295
We didn't get a chance to look at the delay, but we have made a few gaurdian changes that should help mitigate this situation.
We are now increasing the PRM and SRM offlaoding after we transition to 3F before starting the CARM offset reduction. This gives us a bit more headroom when we siwtch the coil dirver. We also moved the coildriver switching sooner (it is now in ISC_DRMI in the LOCKED_3F state) so that we don't waste as much time if this breaks the lock.