Software version: 1.443.1750.12  Problems with the altimeter

Hello everyone, 
I have noticed that my altitude meters are no longer displayed correctly. 
It has been since the last update.
Software version: 1.443.1750.12 
I start at around 586m, after a few minutes it goes to 0 or stays at around 3xx altitude meters. 

Is this a known problem? 
Is it due to the SIM card? 
Thanks for your help
Malik