No. I always cruise at 38/39,000 feet. I only press B when I’m under the trans altitude. When I’m above 18,000 feet I always pull the altimeter knob in my A320 to set to STD altitude, I never press B.
The altimeter jumps when I’m under 18,000 feet on approach. I press B when I passed the trans alt. and it’ll reset to 30.86… So I fly in that altimeter for a while, before suddenly, the Altitude warning alarming, and the altitude indicator shifts by about 500 feet in a milisecond. So I press B and the altimeter suddenly changes to 29.92 on the same altitude which is under 18,000 feet. I’m already on approach so this is even under 10,000 feet. Then after a few minutes of going through the STAR, the Altitude warning alarm goes off again, and it’s still shifts by 500 feet. So I press B again and it switches from 29.92 back to 30.86.
This isn’t normal behaviour. Altimeter shifts from one area or the next tend not to jump that much, should be a gradual differences, like it goes up/down by 0.01 for every difference in barometric pressure that you fly into. You don’t fly at 30.86 in one spot then take a step into another spot and it suddenly becomes 29.92 in the same low altitude.