Sampler tracks lose sound/volume, seemingly at random

I’ll be working on my project, with everything seemingly okay. Then, whenever I load up my project the next day, several sampler tracks will just not sound. I have obviously not performed any changes; I’ve merely loaded the project.

This time 'round, three tracks are affected.

Three sampler tracks seem to be incredibly low volume for some reason. If I turn their volume all the way up in the mixing console, I can faintly hear them, registering at -70 volume or so. If I replace the sample, literally just dragging the very same sample, back into the sampler, everything works again.

Although this “fix” is simple enough, hunting down what’s wrong with your project when you’ve got thirty plus tracks is obviously a massive pain.

Anyone have a clue as to what could be going on here?