rate periodization formula is inconsistent - how do you debug

Summary:

I have a rate periodization formula for spending plans that I have discovered does not always work. Most of the time, it gives the correct answer, but we are finding one-offs where there is a yearly election, but the communicated amount is 0. I planned to use debugging statements to see where it was going wrong, but when I reprocess the life event, it works correctly. To give an example of the scope of the issue, out of 3400 enrollments, 85 have this issue (about 2.5%). So far, every one I reprocessed comes back with the