IKEA Tradfri bulb auto added?

Last night one of my IKEA Tradfri bulbs became temperamental and would not switch on and off despite power cycling it.

So I replaced it with a spare (newer model of the white spectrum bulb)

I put it in the lamp and before I even got to get it in pairing mode or scanned for it from ST app it automagically appeared as a new device.

Is this expected behaviour? I was expecting to have to scan for it at the very least