I've noticed that with the Itch app, game pages will only show regular price, even for games that are on sale. For instance, Home Improvisation currently shows "Available for $9.99 or more" when it's on sale for $7.99.
Yup, known issue unfortunately :( https://github.com/itchio/itch.io/issues/427
I looked through the forum here to see if it was already reported. I didn't think to check GitHub. Thanks for responding.