Since then, devices on the switch's (a WS-12-DC) management VLAN have been showing intermittent connectivity, there's between 20 and 30% packet loss depending on how long a ping is run for. Pings will be coming in normally and stop for between 5-10 seconds randomly. However, if those devices get reconfigured with an IP on a different VLAN of the switch, the issue goes away. So, I get packet loss pinging the management IP of an access point, but not the management IPs of clients connected to it, as they are on a separate VLAN.
I've done as much testing as I can to determine whether it's the site's router, the switch, or the radios, and everything is pointing to the switch at this point. The management VLAN houses only the APs, the switch management, and tech laptop ports. It's sent over to the site's router over a VLAN 1000 on a LACP-A (along with every other VLAN).
I know it's not the router because the issue exists between two devices on the same VLAN with direct L2 connectivity.
I *think* it's not the radios because the issue is only present on this single VLAN going to the radios - others are unaffected. After a re-configuring a backhaul radio (which was showing absolutely no issues) management VLAN to the switch's management VLAN, that backhaul radio then started the same issue.
None of the radios are having issues forming 1G links to the switch, there are no errors showing on any of the switch ports or the radios.
Weird?

We're not in a panic since only the management VLAN is affected, so there's no impact to client traffic. Will be replacing this switch when the weather clears up and will let everyone know what happens...