A single party not editable even by admin for some reason

For some reason one of the parties in one of my customers database is not editable even by the admin account. One can edit the addresses associated with the party, but nothing else. Not the name, not the language, not contact mechanisms, not categories, or identifiers.

I’ve tried to comb through the database to find something that would explain this, but I can’t find anything that would differentiate this one party from all the others that work just fine. What could be the reason for this?

Manually editing the party in the database & adding relations naturally works just fine, but of course this is hardly a solution.

Probably you inactivated the party, so all fields become readonly.
Re-activating the party should make the field writeable. In order to re-activate the party you should check the active checkbox of the party form.

Nope. The Active checkbox is checked, but is also not editable. Also the active column in the database is set to TRUE

Maybe it is due to data incoherence on this record. You should check the log of the client.