I suggest making a script to fix it, rather than fix it manually. It is very easy to use, so basically program then export to excel then run officescript. Also don't tell anyone you made a script, tell them you are doing it manually.
https://learn.microsoft.com/en-us/office/dev/scripts/overview/excel
But you use the same column correct? and the data that is messed up is the same type? Unless the data that is messed up is very hard to detect using a script, it should be possible.