Mac client and jumbo frames

Has anybody experience issues with the MacOS client (2.1.16) and enabling jumbo frames? I’ve been experiencing issues where a backup (300MB tonight) said it would take over a year to complete until I turned off jumbo frames on my Thunderbolt 1Gb ethernet adapter. Once I switch back to automatic/1500 MTU the backup “starts” and completes.

My network supports jumbo frames and works fine with all other components on the Mac except the UrBackup client.

Thoughts? Suggestions? It’s a bit of a pain to reset my network card to get a backup to start. Would setting the maximum speed in the client help out?