Altitude during activity suddenly variable using v17.50

Hi Garmin - Chris. Yes, I'm certainly willing to provide more examples or data if needed.

Comparing the two activities using GPXSee. It's quite clear to see that the path taken is the same.

Elevation seems stable for a while on the right, but then goes crazy for the rest of the activity.

Then, asking GPXSee to also display secondary elevation data (which I assume is DEM, primary being GPS?) we can see that the left activity follows really well. While the right activity follows well for a while, but then suddenly deviates massively.

Could it be that the "automatic" setting for the elevation caused the watch to switch to GPS for elevation, causing the inaccurate values?

Hi Garmin - Chris, I have same issue, I can provide samples before and after upgrade.

Thanks for the quick feedback Chris, I hope this can be resolved.

I can confirm the issue.

Two days ago I recorded a road bike trip. Should have been total 2150 m altitude, Instinct recorded over 2500.

Today a mountainbike tour with 1250 total altitude meters. The watch says 2960 m (up and down with only 12 m difference). If I evalute the gps track I get 4460 m total up and 4600 m total down.

So barometric altimeter does not work correctly and gps track is neither recorded correctly.

If I call it a full fail, that's not wrong, is it?

Garmin - Chris and Luke_ODQA

Small update; I fully reset the watch, used DEM calibration and started a new activity (still on 17.50). The altimeter here is set to "auto" - which I presume means that it will decide by itself how to determine altitude (e.g. pressure or GPS?)

We see the same behavior, the watch altitude is stable for a while but then suddenly spikes out of control. 

Corrected altitude as follows;

A different activity also starts and ends fairly stable, but has large spikes in-between. Also 17.50, also with the sensor on auto mode. In this activity, the entire route is an open field. The only forested area is near the end, which is stable.

For reference, firmware 17.00 was much better, can we roll back to that? The activity below was on 17.00 without any altitude correction applied.

Fortunately i m seeing im not the only One.

Unfortunately this problem Is still on

I've the same issue. Problems on altitude when using my Solar Insitinct for bike or run, no issue when recording hike activities.

Are there any updates on this? thanks