The days count looks wrong
Why the list can say 10 days while the countdown screen says 9 days and 16 hours.
This is nearly always one of two things, and neither is a bug.
The list rounds, the countdown does not
The list shows whole days remaining. The countdown screen shows the exact time left, down to the second.
So an exam at 09:00 tomorrow-but-one, seen at five in the afternoon, is "2 days" in the list and "1 day, 16 hours" on the countdown screen. Both are right; they are answering slightly different questions.
Check the time you set
An exam saved with no time, or with midnight as its time, counts down to the very start of the day rather than to when you actually sit it. If a paper seems to run out a morning early, open it and check the start time.
Time zones
If you have travelled, or your phone has picked up a different time zone, the countdown follows the device. See Exam times look an hour off.
Did this not solve it? Contact us and include what you tried. In the app, Settings then Contact Support attaches the details that help us find your account.