Love the app, wish it didnt "time out"

I really like and use this app regularly. Until the last update I would have given it 5 stars. But recently since the last update it has started timing out and sending me a notification saying "interval run will time out in one minute" while I am using it when my phone screen goes to lock mode or I access another app like pandora or map my run. It didnt used to do that. Not sure what this is about but it makes the app not usable since I am having to stop running, take it off my arm band and go into the phone to let it know Im still using it. I hope this issue is resolved soon or I will have to find another interval running app. Thanks!

Amskeubkdbxksb about Interval Run, v1.8