Hi, we have a Cisco SG500-52P switch, running 220.127.116.11 firmware. Switch is configured with 2 VLN's (VLAN 1 & 2). VLAN 1 is main network traffic and company wireless and is untagged, VLAN 2 is Guest wireless and is tagged. Everything works like a charm except for 1 thing - on VLAN 2, ports GE12 and GE13 regularly revert from their tagged status to "excluded" status in the port to VLAN interface (not to untagged, but to excluded), this causes one access point on the guest network to stop working. This reversion is sometimes just GE12, but sometimes both ports - but never any other ports.
Access points are Cisco WAP321's, all with the current firmware, and all the same settings as they are in 1 cluster.
I reset the ports to tagged, save the settings, and write running config to startup config. Everything works fine for a random, undetermined amount of time (1 day to several weeks) then it reverts again.
When the ports change to excluded and the wireless stops working I log into the admin interface and I am faced with the flashing "save" icon as though a change has been made but not saved. I know I saved the changes - twice in the last instance I saved running to startup and still the save behaviour.
Anyone seen this or have any ideas on what could be going on, or things I can try to resolve this?