That was the answer i was looking for.
Single AI mines should had been changed according to changelog.
-Soviet Field Craft Mines damage increased to 80
-Soviet Field Craft Mines can do damage to a maximum of 1 member in a squad
So unless OP provides a replay i run out of ideas besides calling BS.
I think soviet "field craft mines" describes "trip wire flares" and not mines. PMD and S field mines can damage more 1 models.