Dear Zsolt_a1,
What do you mean by Area/Page Level tracking?
At any time, segment built should adhere to the condition that was used. Changes at Adobe Analytics should never change the condition. Kindly test your condition used in the segment to make sure that the results are conclusive.
If you need more help, you can share the segment condition and results here so that we can validate for you.
Thank You!
Arun