IBM Emulex dual-port 10GbE SFP+ card hangs TrueNAS and Windows at boot and never shows an active link

A used IBM Emulex dual-port 10GbE SFP+ PCIe card (bent bracket, loose heatsink) made both TrueNAS Core and a Windows 10 PC hang for a long time during boot; the switch showed a link but neither OS saw the interface as active. Hardware involved: IBM Emulex dual-port 10GbE SFP+, Chelsio NICs, Intel X550, Mellanox ConnectX-3/ConnectX-2, 10G SFP+.

• Hardware: IBM Emulex dual-port 10GbE SFP+, Chelsio NICs, Intel X550, Mellanox ConnectX-3/ConnectX-2
• Transceivers: 10G SFP+
• Form factor: SFP+

Symptoms / messages:

boot hang with card installed
interface not active