Spotify black screen

It happened to me twice during a workout: while using Spotify on my Forerunner 970, the screen went black. The watch didn’t reset and was still working, but everything stayed black. The only way to fix it is to keep pressing the up button, go to Settings, Music, switch from Spotify to Phone Control, and then everything goes back to normal. Has this happened to any of you? Is this a known bug? Thanks.