The glasses can maintain one active primary connection at a time. Think of the primary connection as the one device the glasses should listen to, such as your phone, Garmin watch or Garmin bike computer.
If several devices try to connect at the same time, they can compete for the connection and cause intermittent pairing.
Choose the device you want to use as the primary connection, disconnect the glasses from the other devices, and then pair them with the selected device.
If a Garmin bike computer will be your primary connection, remove the glasses from your phone's Bluetooth settings and remove the CYBERSIGHT data field from any Garmin watch that may also try to connect. You can then reconnect the glasses to the bike computer.