Xiaomi door-/window ensors doesn’t work anymore well

Since couple of weeks, the Xxiaomi door-/window sensors don’t work anymore very well.
Most of the times it doesn’t react on opening or closing doors.

They worked for more then 6 months well but not anymore.
Use latest firmware and latest Xiaomi app version (Zigbee)

I have 5 of them active and all of them have the same issues.
Anyone with an idea what is going on?