What exactly do you mean here? How can coins get lost by a fork? I get your other point though. Thanks for clarifying.
Oops sorry. My bad.
I was referring to a bug that was present in Bitcoin quite some time ago. The bug allowed the coinbase of two different blocks to be the same. This resulted in one of the two coinbase transactions being invalidated and thus the coins are permanently lost. IIRC, this was the motivation behind BIP30.