An attack of opportunity or an attack from an enemy does NOT take away a character's attack in 5E RAW! This is complete and utter BULLSHIT and how the HELL that made it from testing is beyond me. This needs removed ASAP as this is a game breaking BUG that completely destroys player agency and screws up any combat.
Screw this crap, fix the goddamn BASE GAME MECHANICS AT LEAST!
I don't normally go off like this, but this is crap! How did this simple bug pass QA? Don't turn into BUGthesda, come the hell on.