Can sperm on an OPK cause a false positive?

The only times I've had a positive (or very close to positive) OPK, it's been on a day hubby and I have DTD and I've had (TMI) a bit of leakage onto said OPK. I'd like to think we're just that good and somehow knew I was ovulating, but it seems a bit suss to me that I only ever get positives when we've already had sex.

I've counted the last one as O day because I've had a few of my other O signs, but I'm still curious. Should I be making him wait until I've POAS first?

BTW, I've already googled and the general consensus is no, but I trust BellyBelly more than other lesser forums