In order for Spectrum to successfully poll a device using SNMPv3, we must match the msgAuthoritativeEngineID, the msgAuthoritativeEngineBoots, and the msgAuthoritativeEngineTime records. If these records match and we are using the correct authentication and privacy credentials/algorithms, then we can successfully communicate to the device.
However, if any of these records are out of sync, then the SNMPv3 requests will fail with a PDU reporting back why the request failed. Normally we will see a report of PDU 220.127.116.11.18.104.22.168.1.2.0 (usmStatsNotInTimeWindows), indicating the authoritative engine's boot count or engine time are out of sync, causing the request to fail.
When this happens, a common solution was to initiate a reset in Spectrum, to dump the cached data and do a fresh poll, to get the SNMPv3 profile data in sync with the device. But this reset was not working in Spectrum 10.1.2 and Spectrum 10.2.x.