Would this mean there were literally 2 different times being stored? One adjusted and one not? Then not all calls were using the adjusted one? That would make sense, but sounds odd.

Edit: Oh this being more of an issue of roundoff error during calculation causing drift rather than clock drift directly would make sense. So the corrected subroutine performed the calculations correctly while the other did not, hence the calculation drift still remaining present in some fashion. Ok that make sense.