Hue outdoor sensors dropping off

I have 3 Hue sensors in my smarttings via a DH. They used to work really good but lately im having to repair them constantly. It isnt a reception or battery issue they just don’t want to stay connected for some reason. Any ideas on a cause or fix?

I am having a similar issue with my indoor Ecolink Zigbee Door / Window Sensors
in the last month.