Mobile cellphones are not created for mobile mining, so performance will slow down because of additional load. Mobile mining utilizes the internet, so with increased data usage, it will slow down the network speed, so if you're doing mobile mining, be sure it's not the mobile you're using in your daily activities.
If you want to maximize your mobile mining rewards, use a mobile that is specific to what the mobile mining needs so you can maximize your earnings.
I used to do mobile mining and I have two unused mobile cellphone for my mobile mining ventures.