Vertical displacement and recording time, bug?

I would like to report what I think is a malfunction in the activity log.
When performing activities with vertical development, such as alpinism or via ferrata, in the recording of the activity, the time taken for the vertical movement is considered as rest time.
I suppose when the GPS doesn’t detect horizontal displacement, it considers the activity to be stopped, even if it is gaining vertical altitude.
I detected this bug both in "hiking" mode and in "alpinism" mode.
For example in the last activity I carried out, via ferrata with mainly vertical development, it was recorded 5:17 total hours and only 2:03 hours in motion. It’s at least 2:00 hours away.