Captain Obvious here. Have you cleaned the screen properly?
My iPhone has occasional issues with not seeing swipes et al despite the screen looking really clean. Giving it a good go over sorts it. Was annoyed first time it happened because a clean didn't sort it. Eventually decided to have another go.
Clearly its picking something up. Probably shop "grease". I may have to invest in a cover. Allegedly you need to wait a while after using hand cream. Feels fully dry to you isn't fully dry to the phone.
Not all apps respond the same to fingerpoken. Timer and swipe to answer use more or less the same part of teh screen on my phone. Timer is never an issue, swipe to answer is first to glitch.
Clive