Seems like I'm having similar issue. My firmware is MS15.21.1. Would anyone know if this is still an ongoing issue. Below is the error I'm getting:   9/19/23 16:42 Spanning Tree Port RSTP role change Port 23 designated→disabled 9/19/23 16:42 Switch port Port status change port: 23, old: 1Gfdx, new: down 9/19/23 16:42 Switch port Port cycle ports: 23, downtime: 5 9/19/23 16:42 Switch port Cable test ports: 23   9/19/23 16:31 Spanning Tree Port RSTP role change Port 23 disabled→designated 9/19/23 16:31 Switch port Port status change port: 23, old: down, new: 1Gfdx 9/19/23 16:31 Spanning Tree Port RSTP role change Port 23 designated→disabled 9/19/23 16:31 Switch port Port status change port: 23, old: 1Gfdx, new: down 9/19/23 16:31 Spanning Tree Port RSTP role change Port 23 disabled→designated 9/19/23 16:31 Switch port Port status change port: 23, old: down, new: 1Gfdx 9/19/23 16:30 Switch port Port cycle ports: 23, downtime: 5 9/19/23 15:20 Spanning Tree Port RSTP role change Port 23 designated→disabled 9/19/23 15:20 Switch port Port status change port: 23, old: 100fdx, new: down 9/19/23 15:20 Spanning Tree Port RSTP role change Port 23 disabled→designated ... View more

It is to do with the CPU/code as stated previously, just because a switch can switch more than 1Gb of traffic, it doesn't mean it can generate it or receive it.  If you've ever had to tftp a new firmware to a switch it goes in kBps not mBps. Switching traffic is done in custom hardware that is designed purely to perform that function.  Because APs have to do a lot of different tasks they tend to have generic CPUs that are pretty powerful.  You can tell this by holding an AP that has been on for a while, MR32s in particular get pretty hot!   I tried on my home network and an MR55 gives pretty much the exact circuit throughout whereas an MS220 gives 10Mb.  At one of my work sites an MS225 gets to 14Mb which, to me, proves it is a cpu/code limited test.     ... View more

I believe the reason is that if you remove the cable, the port is still active, so to speak. It is not like you're issuing a "shutdown" on the port. The way to clear the mismatch usually is to correct it, so I guess when you change the VLAN, because the port is not connected to anything, it will accept the change and clear the error. When you change the VLAN back to original VLAN, again, there's nothing to mismatch with on the other side until you connect the cable again and the error appears again.   This is what I think is going on, let me know what you think? ... View more