I'm experiencing essentially the same issue on an MS320-48 (firmware is up-to-date Up to date  Current version: MS 11.17)  All logs still in place as I don't wish to reboot switch and flush logs. Any insight will be appreciated. Issue is seen on multiple ports. port 9: Description Access port on VLAN 10 Tags OFC Access policy Open Link negotiation Auto negotiate (10 Mbps) RSTP Forwarding Port schedule Unscheduled Isolation Disabled UDLD Alert only Port mirroring Not mirroring traffic Port 4: Description Access port on VLAN 1 Tags OFC Access policy Open Link negotiation Auto negotiate (100 Mbps) RSTP Forwarding Port schedule Unscheduled Isolation Disabled UDLD Alert only Port mirroring Not mirroring traffic Jun 25 07:28:01 48-Port Main Switch   Port STP change Port 9 disabled→designated Jun 25 07:28:01 48-Port Main Switch   Port status change port: 9, old: down, new: 10fdx Jun 25 07:27:54 48-Port Main Switch   Port STP change Port 9 designated→disabled Jun 25 07:27:54 48-Port Main Switch   Port status change port: 9, old: 10fdx, new: down Jun 25 07:27:54 48-Port Main Switch   Cable test ports: 9, disrupted_ports: 9 Jun 25 07:27:39 48-Port Main Switch   Port STP change Port 4 disabled→designated Jun 25 07:27:39 48-Port Main Switch   Port status change port: 4, old: down, new: 100fdx Jun 25 07:27:21 48-Port Main Switch   Port STP change Port 4 designated→disabled Jun 25 07:27:21 48-Port Main Switch   Port status change port: 4, old: 100fdx, new: down Jun 25 07:27:21 48-Port Main Switch   Cable test ports: 4, disrupted_ports: 4 Jun 24 20:21:45 48-Port Main Switch   Port STP change Port 9 disabled→designated Jun 24 20:21:45 48-Port Main Switch   Port status change port: 9, old: down, new: 10fdx Jun 24 20:21:41 48-Port Main Switch   Port STP change Port 9 designated→disabled Jun 24 20:21:41 48-Port Main Switch   Port status change port: 9, old: 10fdx, new: down Jun 24 20:21:40 48-Port Main Switch   Port STP change Port 9 disabled→designated Jun 24 20:21:40 48-Port Main Switch   Port status change port: 9, old: down, new: 10fdx Jun 24 20:21:38 48-Port Main Switch   Port STP change Port 9 designated→disabled Jun 24 20:21:38 48-Port Main Switch   Port status change port: 9, old: 100fdx, new: down Jun 24 17:21:43 48-Port Main Switch   Port STP change Port 9 disabled→designated Jun 24 17:21:43 48-Port Main Switch   Port status change port: 9, old: down, new: 100fdx Jun 24 17:21:39 48-Port Main Switch   Port STP change Port 9 designated→disabled Jun 24 17:21:39 48-Port Main Switch   Port status change port: 9, old: 100fdx, new: down Jun 24 17:01:45 48-Port Main Switch   Port STP change Port 8 designated→disabled Jun 24 17:01:45 48-Port Main Switch   Port status change port: 8, old: 100fdx, new: down Jun 24 14:37:17 48-Port Main Switch   Port STP change Port 24 designated→disabled Jun 24 14:37:17 48-Port Main Switch   Port status change port: 24, old: 1Gfdx, new: down Jun 24 12:29:58 48-Port Main Switch   Port STP change Port 5 disabled→designated Jun 24 12:29:58 48-Port Main Switch   Port status change port: 5, old: down, new: 10fdx Jun 24 12:29:56 48-Port Main Switch   Port STP change Port 5 designated→disabled Jun 24 12:29:56 48-Port Main Switch   Port status change port: 5, old: 100fdx, new: down       ... View more