It’s possibly a digitizer issue as the iPad mini is notorious for those kinds of issues. iFixit mini replacement parts are quite good quality however so as Lee suggests, contact support to see what they can do for you. The iPad mini has a few gotchas as far as the digitizer goes, @jessabethany did a [http://www.mendonipadrehab.com/entries/general/the-ultimate-ipad-mini-repair-post|great write-up] several years ago and it still applies today.