the calls can be allocated on the BCCH frequency : the BCCH trx carries 1 BCCH timeslot, 1 SDCCH timeslot and 6 TCH timeslots.
So those 6 calls will be interfered and might have problems to leave this cell.
Incoming MS that are allocated on those TCH timeslots (due to HO) might not be able to connect to those timeslots and will revert to the old channel.
Don’t forget that MS in dedicated mode in cell A is measuring the BCCH of the neighbours. If these bcch are interfered, they might not be able to collect relevant measurements. Therefore one MS might be sent to a neighbour, based on degraded measurements.