Experts:
What can be the reason of rrm pre emption during VoLTE call?
VoLTE call got pre-empted?
Do you see QCI-1 E-RAB release or drop counter due to pre-emption?
It will be rare phenomenon if its happening.
Only emergency services can pre-empt
QCI1 and that too if no capacity is available after releasing all standard-data users.
Depends on the CAC algorithms implemented.
Usually there are pools defined for normal, Hand-in, emergency and HP UEs.
In case of cell overload VoLTE calls may get preempted.