I believe the only medical reason you can get promoted with is being pregnant

So basically you can get passed over?

Yes, can't get promoted unless full duty.

You are passed over while on limited. The only exception is pregnancy.

If you are passed over because you are limited when your number is up and then you become full duty shortly thereafter or months later how long does it take for them to go back to your number Once you're back full duty, is it when the next class goes in?!??

When you become full duty, if they have skipped you already then you will be in the very next class and you will be promoted up front.