I recently found out via a support ticket that sometime in the recent past, we stopped writing back custom attributes to the AO Participants table in order to accommodate an “enhancement” of allowing the mapping of 50 custom fields of any type (rather than limiting admins to 6 string fields, 3 date fields, etc.).
I think we should fix this and do so soon. I have to think most admins would much rather have the ability to easily report on these custom field mappings if the tradeoff is being able to map more fields that they won’t be able to report on anyway. The “solution” I was given was to download a CSV of the participants from the program itself, load that CSV to the MDA, and then join it back to the AO Participants table. This is not scalable. Admins want to be able to map more custom fields because they want to report on them.