If you are reading this thread and looking for the solution, just open a ticket already! Within 10 minutes of my opening a ticket, I had a response with the solution (including the link to the DLL file). Took me 3 minutes to implement, then less than 5 minutes for a successful backup to run. Total time from "I need help" to "fix implemented, tested, and confirmed" was 18 minutes! It has now ran successfully 5x in a row after consistent failures/warnings over the 24 hours before the fix was applied.
Kudos to Veeam for fast turnaround on these support requests!