I’m getting a similar problem.
My friend told about Tixx and his presents while we were in the Infiniraium, so when we finished I went to talk to him with empty bag slots. I clicked for the gift and received nothing, then noticed the chest that was already open and unlootable.
I read this post and found out there’s a Tixx in PvP, which I have now talked to and he gives me the option to receive a gift. I didn’t click on it because I’d rather the PvE rewards.