Bug in Arena after introducing the new adventure

[BigHugger-2468]

This issue is unrelated to the release of the new adventure wing.
The issue and its cause is described in the “common issues” pinned topic:

Hearthstone Common Issues

Here are some of the commonly reported issues that can be resolved. Unable to use specific cards in Adventure Missions Certain card effects are disabled while in Adventure Missions. This is to prevent them from trivializing all of the encounters. Some examples include: Mindbreaker Sideshow Spelleater Grizzled Wizard Golden Cards are not animating on mobile? After installing the Hearthstone app, mobile devices will need to download additional files which contains extra sounds and animatio…