I had the same issue and took mine to the Apple store once I noticed it. Short answer is that they replaced mine after seeing the problem and my new IPP doesn't have the same issue.
But I did see some other strange but related issues with the old, problematic IPP. The Apple store rep understood it was definitely a hardware issue when I showed him everything. Thought I'd put these out there in case it may help when talking to the Apple store genius reps:
Swiping from the home button area to bring out control center (in portrait mode) or multitasking (in landscape mode) didn't work only when I unlocked the device using touch id. If i unlocked the device by entering my password, the swipes worked fine.
When the swipe didn't work, if I went into the Notes App (or any drawing app), and tried drawing around the edges of the screen with my finger, I found that the bottom inch of the screen near the home button just wasn't properly registering input. If I tried to draw with my finger at the bottom edge of the screen (near the home button), instead of drawing a line where I placed my finger, the line ended up an inch above my finger.
When I went took the device to the Apple store, I showed them all of the above. The rep had me do a full software wipe, and the ipad still showed the same problems. So at that point he brought out a replacement which has been working fine.
Hope that helps.