I got this response from another board/forum devoted strictly to High FSH/DOR/POF when I asked if the short LP was associated with the DOR:
"Can be. Short LP means your corpus luteum cyst is deteriorating too fast and not producing enough progesterone. This can mean that your eggs are over mature at the time of ovulation."
To add to the above - the poster from the other board told me this:
"Having high FSH can cause you to recruit follicles too early in your cycle. Sometimes this makes women ovulate early, but if your Lh is slow to respond it can cause your eggs to be "bad" at the time of ovulation." ...that, in turn, results in the corpus luteum not producing enough progesterone.
I thought this was very interesting.