it turn blurry after when the main quest show up on your screen. after the quest are gone.
Known issue, look at the sticky post here:
April 3rd, 2019
Madame Lazul can emote during the Lich King encounter.
Madame Lazul Hero Power is not animating in a match.
Treant minion is missing its portrait art.
April 4th, 2019
Quests that reward both gold and dust have the rewards displayed as a white box on the quest tile.
April 5th, 2019
King Rastakhan Hero Power does not animate.
Magni Bronzebeard Hero Power animation will play twice.
Armor gain animation will play twice.
The Quest popup after a match has ended can cause a full…
(April 5th section)
People have reported that going into the pack opening section and leaving it (no need to open a pack) will clear the blurriness, or starting a game but canceling the queue before you start a game will do so as well.