Cycle length and ovulation confusion

Je

So my cycle is usually around 26-27 days. Ever since I have been logging my positive OPK tests (the 19th this month) it pushes out my expected next period... making it like a 30 day cycle. The last couple cycles have been this way but my period still comes around day 26 or 27. Do you think I’m ovulating later than the app predicts I should be or do you think my OPKs are inaccurate? This is month 5 that we’ve been trying with no success.