On a Heater achievement broken.

My achievement has been stuck at 51% for multiple days now. I first did a timed run of 18 mins and got 11 mins of 4x multiplier. No progress. Restarted the game and got a few more minutes of 4x. Nothing.

Yeaterday, tested it again and nothing. I deleted the cache, removed the download and redownloaded the game. Today, same issue. The achievement is stuck at 51%.