As the title suggest, I would highly suggest to ramp up ORP turret damage to the former 100%, or at the very least give it a significant boost. Offline placing C4 on structures is now a thing sadly, and is not particularly healthy for the game / server. With a mere 10% turret damage while offline, it is possible to achieve this on even significant towers / deathwalls etc.
Alternatively, I believe there might be a setting in OGS to enable auto-decay of C4 on active ORP-structures(?) This would ofcourse also eliminate the problem.