Since I use LR mobile I never got it to download stuff in the background. And with my storing of several hundred albums with the "store locally" function for access without Wifi its a real pain to sync that. Because I have to connect my devices to power, setup the longest timeout for the display and babysit for a long time to get my albums downloaded. Its not happening if the screen turns off, its not happening if the app is in the background.
It has nothing to do with the power-saving settings and battery saver, the permissions and exceptions are all set. And it happens across different devices from different manufacturers.
Come on I can't be the only one that has to connect his phone to a power source, turn the display timeout to its max of 10 minutes and babysit that until LR finished storing my selected albums locally, because it does not happen with the screen turned off.
On top its not even fast storing those smartpreviews on the phone, I've never seen it use all available bandwidht, that makes it even more annoying. Somtimes it just stalls and I have to foreclose the app to get it going again.