Jagged altitude curves

I may have spotted a pattern, a possible root cause, relating to power schemes. In the power mode profiles I have added two power saving schemes, both to maximize battery during GPS. One is with GPS only, external sensors only, no WHR, no phone, no music, light and maps after use. The other is identical, but with WHR only and no external sensors.

I activate the power mode after starting the activity. Either as I wait for GPS lock or a bit into the session, by long pressing the menu button.

The pattern I spot is (and now have repeated) that the first session AFTER I have done a session using one of my power options, will result in a jagged altitude curve. If this second session is in normal power mode, the then following session will have a normal altitude curve. BUT as long as I use my power saver modes, the following session will have a jagged altitude curve.

This is obviously a bug. And I will drop Garmin a mail about it.

A possible remedy, that I will try later this week, is either to only use the normal power mode or do a short dummy session (with a gps-lock) in normal power mode, before the actual session (that can then be in normal or power saver mode for extended battery life).

I guess, that activating a power mode, before or during a session, leaves a changed state afterwards, that is not reset properly.

Do you have any CIQ data fields or watch faces loaded? 

Either way contact Garmin support as it is not right.

No CIQ fields, no third party apps. Only Garmin software. I have mailed Garmin. 

I've been seeing this on the 945 and F6.  I don't do anything with power plans.  On the same outing I'll see it on the 945 but not the F6 even though I have the settings identical as far as I know.  Then on the next outing it might be opposite where I see it on the F6 but not the 945.  Definitely not changing any of the power or calibration settings between these outings where it swaps devices.

I think this is fairly random what triggers it.  Hopefully they are getting a grasp on the cause.  It's showing up in enough devices that I'm sure they are taking it seriously.

True... 

It was not as easy as I thought. Today’s session was not good... really poor with useless altitude data. I even saw lower values as I climbed. Earlier today I did a restart since the watch struggled to connect to my external HR straps. And possibly this affected the outcome (or lack of outcome) on altitude. As I realized that altitude did not accumulate properly, I eventually stopped logging the session, did a manual calibration (to DEM) of altitude, and then continued the session with a new start. After this the altitude curve looks reasonable. For the faulty part, it looks like the altitude was only sampled every 15 to 30 seconds, or so. Given the long time needed to connect to my HR sensors earlier, it is like the sensor hub software goes into some semi-hibernation mode, only polling sensors a few times a minute, and then do not activity properly. I don’t know... it is not good. And the pattern I spotted yesterday did not work today.

I see the same issue

Just downloaded the 2.53 sensor hub beta. Did two very, very short tests that where not jagged or pixelated. One with continuous altitude calibration and one at start only. But these tests was really too short. Will log a longer session tomorrow, with hopes of good and useful altitude measurements.