I've had a LAG setup from a RV340 (ports 2-4) to SG300-28PP (ports 26-28) working with no issues for over a month and just the other week it has stopped working with no changes to settings on either device. I'm at a loss as to why this is. The router and the switch recognize the LAG when all 3 cables are plugged in, but I lose the ability to do anything on the network with any network device as if a loopback is happening instead of LAG of this group of ports. I've removed each cable in the LAG 1 by 1 and it doesn't matter what sequence I do this in, I have issues until I'm down to a single cable. I've dumped all the LAG settings on both the RV340 and the SG300 and rebuilt a LAG to no avail. The only thing I haven't tried is using different ports on the SG300 in the LAG setup, but I don't want a workaround, I want to know why this is happening. Both the RV340 and SG300 are on the latest firmwares. I have this setup in other locations with both a RV340 and a RV345 to SG300 switches with no issues, it's just this single network which luckily is my personal testing network. I'm just really concerned about client networks where I've done this crashing the same way out of nowhere and requiring cables to be removed to get the network up again.