Hey there Russell,
I am experiencing this same issue with the new update, is there any info as to why? We were able to download maps, collect data, sync and then all of a sudden today, we had issues with it. Ran the update and that didn't fix it, any advice?
If you are downloading ArcGIS online basemap, you will run into download issue. We are investigating the issue. Check ArcGIS Online Health Dashboard for the update.