Battery only charging to 89%

My Epix gen 2 is no longer charging to 100%.  A month or so ago, it seemed like sometimes it would charge to 100% and sometimes only to 89%.  Now, starting about a couple weeks ago, the watch will only charge to 89%, no matter how long I leave it plugged in.  Two days ago, it started only charging to 88%.  What is going on here?   

I have had the watch for almost 2 years (got it Christmas 2022).  It's on software version 19.34.  I know I've had 2 or 3 updates since this started happening, but I didn't track the behavior closely with that.