Yep, 541 byte dindex files are empty. Things that make you go, "Uh-oh." - #9 by drwtsn32
In my experience the newer version only prevents the problem going forwards. If you have a functioning database, you can do the trick where you delete the dindex files and have Duplicati regenerate correct ones. I did that on all my systems back in 2020 (after upgrading to a Canary release that included the fix you linked to). After that I’ve never seen a database recreation require dblocks.