turn it on fly into system scan intill the reapers will come fly out of system then re-enter system now you can scan till your hearts content and the reapers wont come
it doesnt stay there for me either but all it requires is to simply wait untill you have started your next mission(as in the action part not choosing your squadmates)and then choosing your powers and they will stay for that mission then simply rinse and repeat every mission its not a big ask
The Origin trainer! Oh and you could have downloaded both and tried them instead of waiting for a response. Just a helpful tip.