Scratching my head over a weird bonding issue

Trying to set up a channel bond into a 10GbE LAG. Set up bonding module, use the ‘miimon=200 mode=802.3ad’ options.
The switch was sending LACP packets, 1/sec to the NICs. The NICs bond formed. But it didn’t seem to negotiate the LACP circuit correctly with the switch. The switch never registered it.
I’ve not seen that one before.
With Mellanox, Arista, Cisco, others like that, the LACP circuit forms correctly and quickly. Here the bond came up on the machine and the LACP bond simply wasn’t active. Though I could see bootp packets over it, thats all I saw.
And I don’t understand why.
Possible NIC incompatibility with the switch? Haven’t seen such a thing in a LONG time. This is a Brocade (a.k.a Extreme Networks) switch. I’ve not used EN in a long time, haven’t used their 10GbE kit.
Will try again next week.