I would like to make LAG connection between SX3008F and SG3452XMPP (both running latest stable firmware) via SM5110-SR modules. If I use only one module on both sides I get stable 10 Gbit connection with no drops, ping is stable etc.. If I try to setup LAG connection (in OC300, latest stable firmware) using two modules on both sides it looks OK in Omada but I immediately get lost pings, about 2-3% and everyone is complaining that network is slow. I tried both static LAG and LACP (one switch active, one switch passive), but results are always the same.

I tried different SFP+ ports on both switches, different LC cables but results are always the same. If I use single module on each side, connection is always stable, it doesn't matter which module I use from 4 I have or what combination with LC cables I try.

Switches are about 80 meters away so DAC cable is not an option.