Application freeze whenever switched to other Application

I don’t know if anyone has faced the similar situation or not. Whenever I switch over any other app or by mistake lock button is pressed, the application gets freezes and the only option lefts is to close the application which results the loss of complete day’s exercise log.

I never faced this.

Never seen this on iPhone. I keep switching to music, news, … What phone are you using?

Cheers
Freddy