Spotify lags after a while (20.87 Public Beta)

I use Spotify to listen to music while I workout. But now on 20.87 beta I can only listen to music for 30-40 mins before the music starts to get "choppy" or "laggy" and I have to stop it and resume on my iPhone instead. One time the watch also just closed the connection to my earbuds repeatedly so I was forced to use my phone again... 

It "feel" like the watch get a memory leak or cpu is hogged or something when this is happening. But I don't know.

I have restarted both normal and cold (by holding the button in until it forces restart). 

My earbuds are the Vista 2.