Spotlights - reddish patch in middle of beam

Is this normal for an led rgb spot? I have bought a few Ajax Online Smart Zigbee Pro GU10 Spotlight Bulbs and on the 30degree ones there is a noticeable reddish patch in the middle of where the beam lands, most noticeable when I have chosen a yellowish colour (orange, olive etc) I know that yellow needs to be made from red and green diodes but I didn't expect them to be arranged so the red would concentrate into the centre. Or is this some other phenomenon?