Chelsio T520-CR not lighting up

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I must be missing something. I hope I'm overlooking something.

Opnsense 21.7.7 running on a Dell R420 with said T520-CR card installed & enabled in /boot/loader.conf.local file.  Interfaces are assigned, cxl0=WAN / cxl1=LAN, with functioning FS SFP-10GLR-31 modules installed.  The T520 interfaces light up when looped together, but when connecting the LAN to a Mikrotik CRS305-1G-4S+IN booting to SwitchOS it will not light up or pass traffic using FS-GB-GE-T SFP modules or the single RJ-45 port.

Any ideas? Am I missing something in the Mikrotik, the Dell BIOS, or in opnsense? The Mikrotik passes traffic on the RJ45 & the SFP ports when feeding it from the built-in copper on the Dell, but not with the TX520.

EDIT: Issue seems to be Mikrotik related. Another firewall with T422-CR cards is exhibiting the same symptoms with the Mikrotik, but not with an Arista switch.

EDIT: Tried using other 10GBASE-LR modules that currently work with the T420-CR card and an Arista switch in another Dell firewall, but still no link.

EDIT: Upgraded T520 boot rom and firmware. Same results. We know light is reaching the destination, but no live link unless we connect SFP to SFP on the card itself.

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Guess I'll install pfSense and see what happens.