I have the same issue since last update (2.2.241). The app itself is also using higher CPU usage, but i can get it to drop to under 1% if i change the theme from daylight to asphalt or asphalt to daylight, whichever one it wasn’t when the PC was restarted.
Like the above poster, one of my cores is at 100%. For comparison, before update both the control service and app would remain at 0–0.1%, after update they bounce between 6–8% (app can be reduced by changing theme as mentioned above). Firefox, with 11 tabs open, 3 of which are youtube, is at 0.3%.
Tried turning a whole bunch of stuff off (Dropbox, Googledrive, Onedrive, skype, VPN, etc) but no change. No games running. No Xbox app.