CiviContribute when you do a search then an action on the search is Profile Update and then choose match selection from top to the rest

and the selection list is multi select (custom data) it can only do one.
For example we have a motivation tag and it is multi select.

If you forget to enter it on say 10 people and search on those 10 and then choose from the search results Do a bulk update based on a profile you then get the page with the 10 people and the multi select list. Once here is you choose say 3 items on the top persons list then click the really helpful button to match this selection to all the rest it can only handle ONE item in the list and will unselect the rest.

Great feature though.