It’s clear that they should have told the referee. Stop the game, or at the next break. Tell him and say look we ****ed up. Rules technically state we can’t do anything (although no one is going to care if they just corrected it 20 seconds after play restarted ). But could have called managers captains together with 4th official. Said look there was a **** up, the goal was clearly onside, spurs are you happy to let lfc walk the ball in?
If spurs then say no then that’s on them and game goes on as normal. Refs should have put the onus back onto the managers to make a decision then and there