Yep. As long as I'm using the phone it will drain my battery. And I'm kinda used in setting it to standby by hand, although my Clearview cover does the same. As does the Samsung galaxy cover on my Galaxy A7.
I have it on because sometimes when I read news articles it goes dark unsuspected. Whether it's because I hold it slightly tilted or just
poor registration I don't know. But the A7 does the same. Sometimes it works, sometimes not. Hence the 1 minute.