This may not only occur in Heroic Dalaran, but that’s where i’m finding it. (Also I only play on Iphone).
Every time I get Bob or it’s robot substitute (twice in a run), the accept button of the explanation box freezes and you cannot enter the tavern.
The only way i’ve found to carry on is close the HS App and get back in quickly. (If you close the app and get back on later in the day you find the explanation box and have to close and open)