EDIT fixed in the murder mystery client release. of 27 July. but it should never have been broken in a client release.
iPad Air 3 here., latest iOS. With the latest Hearthstone client, the filter at bottom left is empty, so looking at card sets can no longer be done, as individual card sets, or standard, wild, or classic, cannot be selected.
iPhone clients are not affected, filter button works fine.
There are terms for this: bug, regression.
And, with the challenge-friend problem and crashing on switching servers, Iām going to add: quality control.
Really, the Hearthstone client model and code base is years old. These issues should not be appearing.