No matter what the label says, there's always a possibility that
1) she bought her OPI acrylic from an unreputable source and it isn't what she thinks it is, or
2) She's been decanting cheaper MMA product into her OPI containers herself.
3) She's using really old stock and the OPI product has "gone off"?
We have all heard of techs wanting to cut corners, and she may be one of them (I'm not pointing fingers, though - there may be a very legitimate reason for the fishy smell!)
Acrylic monomer smells strong, but it shouldn't smell fishy.