Strange timesheet behavior in Project Server 2019

Hello.

We have strange timesheet behavior in Project Server 2019 (16.0.10337.12109).

If we first time create timesheet for user in current opened PWA period, Project Server don't create timesheet lines. We need edit cells with zero and save timesheet for creating timesheet lines.

BUT, if we delete this timesheet and recreate it again, Project Server create new timesheet with new Guid but with previously created timesheet lines.

Why this is so?

BR, Vasily