Conflicting OPK Answers AM vs PM

Hi, I have been tracking my surge all week. I tested at 6am and 10am yesterday, both negative. Then at 5pm, I tested and it was positive. I tested this morning just to see and it was a blank circle. However, I then used a different port (what you put the stick into) with the same urine and it was positive on that one. I did another one a little bit ago with that same port (Same as earlier this morning that was positive) and now its negative. Help!