All three affected switches are using out-of-band management, plugged into one of the ge- ports on the same switch
When the interface is plugged/unplugged, the switch records up/down activity on both the me interface and the ge interface that it is plugged in to.
Swapping the connection to another, similarly configured ge port has no effect; plugging other things into the ge port works normally. The switch appears to be switching properly; configuration changes made through the console appear to be taking effect properly.
Only one of the affected switches was directly involved in the network loop, although all switches saw the resulting storm.
Naturally, I would prefer not to reboot these switches. Does anyone know how I might resurrect the network connectivity of the management interface without a reboot?