I created a new blank form in InfoPath. Published it to a new document library. Then I made a minor change and tried to update that same library. Same issue appeared.
In the mean time I've been doing the local publish and upload workaround, which works fine enough.
Then I discovered another similar issue.
The documents created with this Infopath form ALSO cannot be updated after they are submitted. The error I get when trying to edit an existing document in Infopath is...
This form cannot be filled out because you do not have adequate permission, another user has the form open, or the form is open in another program.
Do you want to open a read-only copy of the form?
This sounds suspiciously like my template issue. Certainly no one else has the document open. I have full admin. This happens regardless of whether I check out the document prior to editing or not. BUT if I set the library up to use versioning this does NOT happen. See? I can always post, but never update - both with templates and documents.
Regards, BPM