Hi,
if you’d like me to look info the dump to check for obvious and non-obvious issues, feel free to send me the tcpdump file to jmozdzen@nde.ag - I’m under NDA, so everything will be handled confidentially. If not already done this way, I’d be interested mostly in a tcpdump taken on the SLES12 client machine, as that one ought to work anyhow.
Regards,
Jens