In the post time page, approved/unposted time entries are not displayed for posting.
This happens when Labor Cost is blank on the Employee record when Time Entry was created.
If Labor Cost is set to null on the Employee record, then the cost of the Time Entry cannot be determined. If that is the case, it is not available for posting because the cost is null. Thus, the system does not have the basis to compute the amount of cost to be posted on specific accounts.