I am not sure f something changed or I wasn't paying attention, but I thought that sync would use mobile data even if the update settings said not to.

Both my devices are set to update while I sleep on my home network. On the war to work, I use my phone connected to a bluetooth stereo to listen to some shows. When I get to work, my tablet connects to my work's wifi to sync what the phone did on the way. I don't want my phone connecting to wifi at work due to firewall restrictions. But lately I have noticed that my phone's sync logs states that sync failed because I am on a mobile network, which is forbidden. I am pretty sure that I had the same settings (update on wifi only) in the past, but sync worked as I just described.

Is there a separate setting to allow sync to use mobile data if updates cannot (if not, can we?)? Was this something that changed, or was I allowing mobile data for updates the whole time and not aware?