When I was testing the window sensors, I removed one and as I got closer to the panel it reported a tamper. When I put it back on the window, initially the tamper didn’t clear. At some point it cleared but then send the window was open. I went and opened and closed the window. The window open message cleared. When I opened the window again, no open window message was generated.
Just to be sure we are not overlooking something, how are you testing? This kind of open/close behavior would be expected when viewing the status through the app. There is a 3 minute delay on the same status from displaying again for a single sensor. Here is a guide to how sensor activity displays in the app/website:
If you are going by what the local panel reports however, this description would suggest that the panel is just having trouble listening to the RF signals.
Where is the panel located? Is it near large metal sources? Has any appliance etc. been added around it recently?