Forerunner 265s elevation gain and floors climb issue

I am having some elevation gain and floors climb issue in the last 2 months. I noticed it in early December. It might have happened after a software update but I am not sure which one.

If you look at the floor climbs graph above, you can see that starting in December, the stats just went crazy. There are days that when I am walking around the same floor at work and my watch will notify me that I climbed 10x floors. This never happened before December.

 

Here is the weekly stat. There is no way I climbed 300 floors in the week of December 6 - 12. My weekly average for the whole year was around 100 and it was very consistent. 

      

Here are three runs that I did around my neighborhood which is completely flat. It is so flat that there should not be any elevation. The first two were in Jan 2024 and April 2024. I am ok with having 10m or so elevation error. The third run was in Jan 2025. It recorded a 42m elevation gain. This error is unacceptable at all. This happened to all my runs starting in December 2024. I ran the same route almost every time but the elevation gain could range from 20m to 60m. I thought this might go away after some software updates but it is still happening as of my last run on Jan 14, 2025. Has anyone experience similar issue? I am hoping this is a software issue but now I am thinking if this is a hardware issue because my coworker has the same watch and her watch doesn't have this issue.   

  • That thing with the floors can happen on days with a lot wind. Maybe also the elevation. My 265s has also problems with elevation. I always come back several meters below, although it's the point where I started. Or I went down 23m during sitting in my living room, no barometer change. Garmin told me that this behavior is normal and within the range... And yes, at least my 265 that I bought because of the larger display shows a similar behavior.