Interface models are disappearing and then reappearing in Spectrum after the device model is reconfigured.
If Spectrum detects the interface model is stale (meaning the configuration of that interface model is no longer seen in the interfaces mib of the device), Spectrum starts a timer of 120 minutes. After 120 minutes, if the model is still stale, than Spectrum will automatically delete the interface model.
Then, if the device model in Spectrum is reconfigured and the configuration for that interface is back in the interfaces mib, then the interface model will be recreated.
Release : Any Spectrum release
Component : Spectrum Core / SpectroSERVER
The PortAgeOutTime attribute id 0x129db on the device model controls how long Spectrum waits before deleting a stale interface model. The default value is 120 minutes. This can be increased or decreased by the user to suite their needs.