The only two ways I know for stabilizer to disappear are to drain the pool OR to experience a major 'slime-out' with algae and bacteria.

As best I can tell, you haven't drained, and you haven't had a slime-out since you last tested. So?? I don't know.

Possibly, either your original tests OR your recent ones were wrong. But the lack of chlorine loss during the night, with chlorine loss during the day, suggests no CYA, but also no residual ammonia from a 'slime-out' eating the stabilizer.

I don't know where your stabilizer went, but it seems to be gone. Go ahead and use what you've got, and the tabs you've got.