Passiv DWDM Multiplexer - Overdrive?

Merry Christmas everybody!

I ask my self if its possible to damage passive optical Equipment like a multiplexer by overdrive it, for example if the signal is too high or if we miss the attenuators for it.

That its possible for active Equipment like an sfp module i know. For example with 10G-ER (40km) the Damage thereshold is 5db.

So i wonder if this can also happen with passive Equipment lile a multiplexer?

thanks