I upgraded to 7.8.3 which is supposed to fix #MODULE-7114 however, descriptors have not been fixed as far as I can see.
This is how it should look like:
And this is how it looks like now (the 7.8.3 update was applied on Sep 25th):
Only payments charged via the daily cron at 9:00AM appear correct. Payments done by the customers themselves don't show the invoice number and the statement descriptor shows up twice: