You missed my update in that same posting. I don’t expience the crashing anymore but a MTU of 1500 or even 1508 (rfc4638) is not working. Because 7.1betaX is not working at all with me I don’t see the effort of rewiring my fiber to a NTU and connect it to a ether port to see it probally still not working.
The SFP is fine and it has a MTU of 1592.
My previous attempt was worse and now it works much better: v7.1beta2 [development] is released!