Originally Posted by Blizzard Entertainment
We just released a new patch for Heroes of the Storm in order to make an adjustment to the in-game UI.

User Interface
Party Frames

  • We’ve temporarily disabled the ability to interact with Party Frames at the top of the screen in-game due to an issue affecting Pings. We apologize for any inconvenience as we work to address this issue, and we will keep you updated as we approach a fix.

We also released a new balance patch for Heroes of the Storm on December 20, which featured adjustments for Heroes like Garrosh, Hanzo, and many more. Click here to review the balance patch notes.
Source: The Bnet launcher