Weird incompatibility between Marvell SFP+ adapter and Cisco switch
I recently got a free (ewaste) 48 port + 4 SFP 1G Cisco Catalyst 2960-S switch and have been trying to get fiber working on it. I bought some Cisco-compatible SFP transceivers (10Gtek ASF13-24-10-D) and connected it to my Mac via a QNAP Thunderbolt to SFP+ adapter, which uses a Marvell AQC100S internally. This is primarily a 10G adapter, but it works fine with most devices at 1G as well.
However, when connected to the Cisco switch, the switch doesn't show the link as up, while the QNAP adapter does. The switch has no link light, and reports no packet errors or anything on the port. Meanwhile macOS thinks the port is up just fine and tries to send packets.
If either side is replaced with an Intel I210 card using the same SFP transceivers, everything works normally. QNAP --fiber--> I210 is fine, and I210 --fiber--> switch is fine. To me, this indicates the transceivers are compatible, and the QNAP adapter is capable of working with a 1G fiber connection, but the Cisco switch is expecting something that the I210 provides but the AQC100S does not. Any ideas or similar experiences?