While not quite like that, the airline could totally "upgrade" your specific ticket to A-->C, or A-->Z-->C, and then you have a problem.

Or even a later A-->B segment that still gets you to C on time, which may not work for you.

This isn't really unlikely because the airline knows your desired A-->B trip is really valuable (which is why you skiplagged in the first place!).

One reason airlines like selling flights with connections at a discount is because it gives them flexibility to get you to your "C" destination on time.