I use a ( Knock Lock ) application, before in the ( kitket Flyme OS 4.2.0.5 ) with the same application does not have this problem, but now ( Flyme OS 5.5.12.22 ) I have a problem and allow access to be able to work, but when the phone would fall asleep after a short time - the ( Knock Lock ) application is killed, the phone is working again without locking - normally lock that was set from the system. Also do when cleaning the cache memory sometimes stops working ( Knock Lock ) apps, that me it makes me nervous.

This application I’m very accustomed and I want to use the Flyme OS 5.5.12.29 test

Can anyone help me how to prevent this for me killing my ( Knock Lock ) application
now use Flyme OS 5.5.12.22 test and update to 5.5.12.29 or need to wait for a new update to improve the system.