The problem is the target screen is continuously being updated by an animated Icon or some kind of continuous animation which is causing CountDown to constantly capture the screen from the device. This will leave no CPU time left for other CountDown tasks.
Increase the "Screen Capture Poll Rate":
Change "Screen Capture Poll Rate" from 250 mSec to a value something like 1000 mSec. (Try to optimize this value to match your device.)
The default "Screen Capture Poll Rate" is 250 mSec. CountDown will check to see if the target screen has changed every 250 mSec and if a change occurred, CountDown will capture the screen again.
Increasing this value too much will result in slower screen update response.
Increasing this value not enough will result in CountDown being too busy capturing the screen to do anything else.