Fouled board in ClubTeams
The concept of a fouled board exists in ClubPairs but not ClubTeams.
We had a duplicated board in last night's multiple teams. It was spotted on the second round, so two teams played one variant of board 19 and everyone else played a second one.
This did not affect the scoring of the event but the cross imping, of so much concern to some, is now wrong. It would be useful if we could mark two of the results as fouled boards, for the purposes of cross imping.

Comments
I think we usually just remove the results for XIMPs/NGS and reinstate them for the main results and master points.
You could just mark the board as 50/50. Presumably there was no comparison available anyawy with teammates so you need to do that anyway??
Team 7 NS played board 19 against 2EW on the first round. At the start of the second round it was discovered that boards 18 and 19 were identical. So we replaced board 19 with a new board and kept the original board 19 for when 2NS played 7EW.
We also needed to put a new board 18 for when Team 2 played it (fortunately team 7 were not scheduled to play board 18).
So boards 18 and 19 end up with two results that were played with different boards, but the results are still valid and should be retained for scoring purposes.
It is analogous to a scoring a sub-field in a pairs event, at least from the cross imps perspective.
https://berwickbridgeclub.co.uk/
That's awkward!! I think adding Fouled Boards capability would not be a simple fix and it is a rare situation. I suppose you best follow Gordon's advice above to temporarily remove the results for the Ximps.
It's what the EBL/WBF do (not with EBUScore) when they put in a substitute board, usually because a pair has arrived late and would have been in a position where they could have seen a board on vu-graph.