Hi,
You should raise_objection() and drop_objection() in the run_phase() of your test.Do not use them in any components or sequences as it is difficult to track down. By using these in your tests, you will only have one outstanding objection per test.
Drain time is an additional amount of time that the run_phase() will execute after all objections are dropped. This can be set in test it self for any additional processing time needed after all your test sequences have completed.
I think this will help