I spoke with the Phillips lighting rep today. He is as baffled as myself and the supply house manager. Rep suggested that I remove lamps, power off fixtures, and reinstall the lamps. He thought that since I installed them in "hot" fixtures that could casue an issue. The supply house has ordered a new box of lamps and 4 new ballasts at request of rep, to try and correct the issue. I will see tomorrow what happens.
Well, the problem is resolved. I simply replaced the lamps with some new ones from a different case. We actually changed the color of lamps as well. The problem lamps were 841's and I now have 735's in there. Magically....no problems now.