Slow refresh of mail when switching between work and personal on BB Classic

We are piloting the BB Classic and pilot users are complaining about slow refresh of the Hub shen switching between work and personal workspaces. The only account in the work space is our corporate Outlook email. User's can have whatever they want in personal including gmail, aol, facebook, twitter, etc.

We are running the latest OS version 10.3.2.516
We are using T-Mobile devices.
Corporate email is Outlook/Exchange

I've seen a couple of companies report the same issue. You might want to consider opening a support line to BlackBerry direct and see if its a specific mail type and compatibility that is causing the issue ...