Assessment Mode and Assessment period: Time difference

We have a setting where the lecturer uses the "Assesment Mode" and the "Set assessment period" paramtere fot the test element and the "Time limit".

Every time a question is answered the time limit is shortened depending on the duration the user stayed at the question.

The Test time limit is "stable" but the other counter is running down faster.

Compare the 2 Screenshots from the same test run taken in a 2min interval , the test time limit is approx. 2 min apart and the other counter 5 minutes..