Im trying to troubleshoot an issue Ive had for well, months or even more than a year.

I have an x86 router with a PCI express NIC that reports an L2MTU of 9014, my switch is capable of jumbo frames up to 9216 and is configured as such.

But for the life of me I CAN NOT get a packet from this router, thru the switch that is greater than MTU=1500.
Not even 1501 works.

Has anyone seen a card report an L2MTU, but still not properly work?
Has anyone seen a net gear smart switch not pass packets larger than 1500?