John,
You have indicated that there is no night destination in the "listed directory numbers" field.
You have 4331 as the night service activating ext. under console para.
You have 4331 as day, and 4501 as night in the trunk gp 5.
You had 4331 as the incoming #, bus1, day 4331, night as 4501. Under Bus1 you indicate M>F 8:30>5:30 so Annie answers as 4331 during that time, before and after should have gone to 4501 internally regardless.
The switch sends info as to day/night mode in its messaging, the only suggestion I can think of to make is remove Bus1 from the AA routing table and see if it will work that way following the switch mode.
Other than that I am out of ideas, The switch and voicemail are strickly logical they only do what they are told or act on what they are given.
Something would have to be interfearing to cause it to act or respond incorrectly.
If you cannot resolve this with the information that I have given, you will probably have to try to find a tech in your area to work on this, because I don't know what else to suggest.