I’m not entirely sure what “uphold the completion” would mean (given that the actions weren’t completed correctly). I assume it’s something like “change the gamestate to what it would be if these actions had been performed correctly in the first place” – is there are clearer way to word it?

They were completed though. They were improperly completed, but I think “uphold the completion” gets the “they were properly completed” message across

The uphold keyword is actually usefully defined four this particular situation:

To Uphold an illegal action is to retroactively declare the attempt to take it to have been successful, and to declare that all attempted game actions taken after it were attempted as if the Upheld action had been successful.