Ovulation

It is, but that would be considered a short luteal phase. The most likely scenario here is that your period will be delayed to match your usually luteal phase length. Usually your luteal phase doesn't change but the follicular phase can. So if you're ovulating later than expected, your period will likely be later than expected

It’s definitely possible.
More likely you ovulated late, or you could have underlying PCOS which would mean you always have LH in your system, can give false positives