Reconnect media issue in Motion 4

[Em Malden]

Hi guys,

I think this is a fairly simple issue, but I've tried to search for threads on it and can't find any.
Occasionally I've moved media that is used in a Motion project by accident (tut tut) and then needed to reconnect it within the project.
I recently had to do this on a project which uses a 'hold frame' timing filter on some footage and then a bezier mask to cut out the character in that frame. When the media is reconnected, the clip appears to be out of sync and the hold frame applied to the wrong part of the clip, meaning the bezier is not cutting out the character.
The clip I have relinked is exactly the same clip as I was using before, I literally just moved it to a different folder in finder.
I can't see any reason why the reconnected clip should come in out of sync and there is no easy fix once it has, other than rebuilding the hold and redrawing the mark (teeeeedious)
Any clues/advice would be much appreciated.
Many thanks
Emily