It is a push-push connector, so usually you would always push to eject. It is a similar mechanism as for some ballpoint pens (push once to get the tip out, push again to retract it). Maybe your card is getting stuck by some friction on eject. You can use tweezers to carefully pull it out, just be very gentle and do no pull too hard. If it looks like it is not coming out, maype push it all the way in once more and then try to pull it out with the tweezers. It should get better after a few in/out cycles. Sometimes the connectors get a bit sticky during soldering but this corrects with more use.