has anyone ever had an ovulation kit start turning positive then stop before it was as dark as the…

has anyone ever had an ovulation kit start turning positive then stop before it was as dark as the test strip?... I've been tracking my ovulation for months now and this is the first month that did this.. I did stop taking the evening Primrose and the borage oil Saturday when it started to turn then it stopped turning... kinda concerned I might not ovulate this month