I've had that happen in the past too. I still think your OPK is correct, though, unless you have some hormonal imbalance. There's a sperm-friendly lubricant you can use at the time of your LH surge, if you don't have much cm of your own. It's called Pre Seed. But make sure you take advantage of the more abundant cm, too, even if it is a few days before you o. Sperm can live up to five days inside you, so there's still a chance those early swimmers can get up there too :-)
Good luck!
Yes. I go with CM. Whenever I saw my CM eggwhite raw type, I go ahead and have imtimate. sometimes you got +LH due to you have many tiny follicles and that follicles release LH. go with your body CM is the best.
This month I tested LH and got + on cycle day 7 and didn't ovulate until CD 14 becuase my CM changed.
Hope this help.