No, Im'm not using CBD at all, only Web UI.

Thank you for your investigation. Unfortunately, I don't have a spare SFP modules to test. On port GE27 and GE28 there are Cisco SFP-1000Base-SX (PID: SFP-1000-SX), serial umber starting from AGMXXXXXXXX.I also compared GE27 and GE28 port settings an...

Here you have a log with FW 4.1.7.26 and working LAG, then with FW 4.1.9.85 when LAG stopped working.

I have exactly the same issue, C1300-24T-4G (switch3) with configured LAG on GE27 and GE28 (LACP Enabled, Flow Control Enabled) and connected to Cisco Business CBS250-24T-4G (switch2) - LAG stopped working after upgrading FW from 4.1.7.26 to 4.1.9.85...