I noticed too, I use my app for a rough guide but I can tell when I ovulate as I feel it.
I used Ovia and it has always been accurate for me..
My period app was accurate at tracking my ovluation. I used it along with first response ovu tests and the first response app, and it was accurate in predictong when my ovulation was at a peak. But everyone is different
The apps are for you to record and track data, the apps can make predictions based on the data you put in, some are better than others at doing that but if you’re only putting in the dates of your periods it has basically nothing to go on. At the end of the day predictions are only ever a guess, even if you’re inputting a lot of data
Period only tracking apps aren't very accurate. I used the pre-mom app, and it was pretty accurate. But i was also tracking my basal body temperature and taking the ovulation test when the app indicated based on my LMP. With all that data in the app, I got pregnant naturally twice. Also, there's only a 15% chance of getting pregnant per cycle. Which seems crazy low lol