Static IP seem to be stucked after unexpected power cut on other side (raspberry pi 3b +)

I have a Raspberry Pi 3B+ connected to OpenWRT router which is a TPLINK router originally.

I have noticed it already several times the following scenario:

  • Setup static IP for Raspberry Pi 3B+ on OpenWRT side
  • Connect RPI3B+ via Wifi to the router, wait to confirm that IP is assigned to it.
  • Cut power immediately on RPI3B+
  • Power on RPI3B+ and expect to get the same static IP as it before
  • No IP address received (waited hours)
  • Restart router
  • Restart RPI -> IP is assigned

It seems that static IP address is stuck somehow in OpenWRT database after unexpected connection lost on other side.

Any idea what should be configure to avoid this? I have other machines connected via Wifi or LAN but I did'nt see this problem on other setups.

Thanks

Enable logging on the DHCP server, and watch the logs to see what's happening.