I don't think it's possible that it's still trying to track the first quest (since it gave you the icon for it). Receiving the icon should indicate to the system that you are no longer doing that objective (we have tracking for both achieving and then redeeming the icon itself). I think the more likely reason is for some reason, it's not registering that you started the second quest. Either the message is failing to get to the server (and our logging isn't tracking it), or it's getting there but being rejected.
It should track in real time, with up to a few minutes delay. However, it's true there may be getting something dropped.
I'm glad it's working for you now ! And sorry you lost your progress :(
I will bring these reproduction steps to the team and see if we tested this case/if there's anything they suspect, given that info.
Thank you for the information!