Altimeter Messed Up

Hi all,
I've noticed that lately my planes' altimeter is zero'd at 3500 rather than 0, tried to lower it but when the message appears that my altimeter is set wrong and to press B to reset, it goes back to 3500,,,
Is there something I don't know about how to adjust this?
Happened on the Dash 8, EMB190 and A320 planes which were fine before that...
Thanks,
Robby
I've noticed that lately my planes' altimeter is zero'd at 3500 rather than 0, tried to lower it but when the message appears that my altimeter is set wrong and to press B to reset, it goes back to 3500,,,
Is there something I don't know about how to adjust this?
Happened on the Dash 8, EMB190 and A320 planes which were fine before that...
Thanks,
Robby