I wish I had some advice. I really don't but your chart doesn't look like you Oed yet. Temps are a little crazy
I know they say a side effect of the polyps I have cause breakthough bleeding. I would call your doctor to see what he/she says. I am not sure if others things could cause that? Like a cyst...or fibroids?
I hope your temps get a little more stable. I will be stalking your chart

Like Dee I have heard ovulation can cause spotting. I hope that's the case for you.