Every time I click on anyone in my friend list, Earthstone close/crash. The button to duel/watch still work tough. This happen on last IOS on my Iphone XR. My sons play on an IPad and has exact symptoms. This started at last expansion of the game. Its a bit anoying… 
Same here since last expansion
iPad Pro 9.7 MLYJ2NF/A
iOS 13.2 (17B84)
Hearthstone 15.6.36453
Game crashes :
-When clicking on a friend to start a chat
-When clicking on add friend button
Thread with similar issue here:
Same for me the game crash when I try to chat with friends