Question

I have taken an OPK several months while TTC and it is the advanced clear blue easy ones.  It shows high fertility with a blinking smiley and peak with a constant smiley.  Normally the stick shows high fertility a day or two prior to peak fertility, however this month I am still testing and am on day four of high fertility not peak.  Has anyone else had this happen?  I tested two times yesterday and will do the same today but so far it's only high?