I would think you may have a few contributing factors. Blade tension
may be to low. As the blade is being used it will stretch, you may need
to adjust. Double check you guides, upper and lower. Some drift is
normal, and if using a fence, adjust the fence for the drift.
Changing grain in the material will also contribute to drift.
Have you cleaned the rubber on the wheels? This problem shows itself by
the blade not tracking true. Working green wood would leave residue on
the blade and be deposited on the wheels.
Do you have another blade? Try it. Could you have cut through a nail
that might have contributed to premature failure? I've not done much
re-sawing, but this has happened to me. This was not noticed when
cutting on the bandsaw, but did show itself on my jointer with chipped