IKEA’s implementation of Zigbee has a non-standard addition to allow local control without a hub - the instructions usually show holding the remote next to a bulb to represent this option.
If you press the pair button too long / too many times / when a random event happens the remote pairs directly with the nearest device that responds.
For me, pairing a new IKEA remote sometimes paired not with my Zigbee coordnator, but with a nearby Lidl light bulb. The fix is to factory reset BOTH the controlled device and the remote and try again.
BTW - the IKEA factory reset sometimes isn’t a >10S press on the remote, but 4x presses in 5seconds or for light sources, toggle the main switch 6 times.
If this helps, 
this post!