Elevation question

The two elevation profiles below were runs on the same 3 miles of a relatively flat rail trail.  I run this almost every time I run. There's a slight incline on the way out, so a decline on the return.  The first image was from my run today using my Fenix 6S and the second was using my 945 a few weeks ago.  Why is it so choppy with the Fenix and smooth with the 945?  This was my very first run with the Fenix so I have nothing to compare it to.  Just want to confirm there's no problem with it.