iOS automatically locks out in iphone every 1-5 mins as part of security. Downloading a collection does not seem to work in background mode, either when the pjone locks itself or when another app taking presence of the screen. I have checked the list of Background Refresh Apps and Lightroom is not listed in it and so confirmed the support team via chat.
Assuming the above is true this means that feature is rendered useless for any practical use (download of collections of more than 20 photos). I was wondering wether anyone has encountered any workaround until background refresh gets added to the app?
Turn of the iOS lock temporarily. Allow the download to occur when you are not doing anything else with the phone. Connect to fast network if you don't want to use data. If you have data to use, turn off wifi to force usage of data for download.
Its a shame it doesn't work in the background but hardly renders it useless.