One of the strangest (and funniest) things I've ever seen was a couple years ago during a 9th-week (televised) game to determine play-off eligibility. The game ended in a tie. In one of the play-off periods, during a 1st down running play, there was a BIG loss but the runner was tackled by the facemask. Of course, after enforcement, should have left the offense with 1st and goal from the 25 (if my memory serves me correctly) yd line.
However, the officials got "confused" and, after enforcement, re-set the chains making it 1st and 10!!
At some point, prior to the next RFP, someone from the defensive sideline realized the mistake, called time out and asked for a conference with the R. The officials listened but could not agree on the correct enforcement during the OT. Finally, apparently, someone suggested they look at the rule - but there WAS no rulebook around. Someone on the sideline (maybe a non-working official) told the team questioning the enforcement that he had one in his car. They dispatched him to get it; and 20 minutes later, he returned, The officials looked up the appropriate case book play and, fortunately, corrected the error.