Maybe this is not really a bug, but if employee account on time tracking system has been (re-)used before the employee is registered as "in" in the employear system, the total worked time of the month also includes that time of the previous records.
The registered time in the time tracker data should be counted only from the employear "date in" (at least in my case - if new employee did some test time that you want to include, you might disagree).
Not sure this is a bug: if it is a new employee, he should have a unique employee id, also in the time tracker system. If he worked before as interim, he should have another (interim-) id in the time tracker system.
You can move the time tracker data of before empoyear date-in to another account there.