Searching/Filtering/Updating by special characters seems to work for the most part with the exception of a multiple choice field.
With Multiple choice type fields, if one of the options is a ? (or even ???) then searching or filtering by this field for ? or ??? returns the full list of records, even if the field only contains a ? and your search filter uses 'is' (and not contains)
This doesn't occur with other standard text type fields which will easily return a list of only the required fields.