Rare disconnection

is there a known issue that cause bulbs and LED strip to be knocked offline? does not happen often but it has happened few times. symptoms are:

  1. blue led is lit, indicating it’s connected to WiFi
  2. affected bulbs & LED strips show as “offline” in yeelight app - unable to control
  3. other bulbs/LED strips that are not affected, show normally in app and works normally.
  4. the router WiFi is working fine, as other devices phone, laptops, webcams etc are operating normally.
  5. forced to switch off the main for the affected bulbs/LED strip and switch back on, wait for it to reconnect to WiFi
  6. yeelight app refreshes and show all online