Before Summer ’21, If records include a Geolocation field and the variable containing them is used as the input of something else, an error would occur. This was fixed in Summer ’21. The fundamental issue is that Flow doesn’t support Location. However, it wasn’t preventing the use of Location in merge fields. Automatic Output Handling exacerbates this problem: if you assign an automatic output to the input of something else, the Automatic Output system essentially tries to merge the needed fields. If the input you’re using is to a ‘black box’ object like a Flow Action or Flow Screen Component (where we don’t know which fields you’re truly going to need) Flow assumes you’ll need every field and tries to pass in Location. At this point the error would occur.
The fix involved improving save-time validation to filter out location fields. This prevents automatic output handling from causing errors with records using geolocation fields.
Additional work is planned for Winter ’22 to fully support geolocation fields