LOD penalty on 4th Down

[buckrog64]

I should clarify...on OP I didn't do a good job explaining second play...LOD on 2 pt. conversion attempt that fails...iow, incomplete pass during a play on which A committed OPI....don't replay down, but do you still assess yardage for penalty?

First play, A65 caught thrown ball behind line of scrimmage and ran down field where he was tackled. I would guess the debate was first where the ball was caught because I think behind LOS is touching and beyond is OPI, if I remember what I read in the book.