Receiving tamper alerts, specifically camera obstruction type, when there is no real tampering.
Heavy water mist from sprinklers, car washing or other source can trip a cameras internal sensor so that it thinks someone is spray painting the camera lens or dome.
This depends on the system. If you cannot login to the NVR to directly disable this setting, you may have to log into the camera directly and see if you can disable or modify this setting.
Installed 2 Avigilon cameras inside a car wash. Every time someone used the car wash the owner would receive tamper alerts.