Cannot log users off machines for local administration

Our team have recently upgraded from Teamviewer 10 to Teamviewer 14. However, this has caused issues with remote administration of PCs for our customers.

Previously, we were able to use the Remote Log Off option to log a user off their machine. This would disconnect and then reconnect Teamviewer automatically, bringing us back to their login screen where we could then log in using a local admin account. We are still able to do this with Teamviewer 14 for customers who still have the Teamviewer QuickSupport 10 client on their machine via Actions > Lock > Sign Out On Remote Computer. However, customers who have downloaded the QuickSupport 14 client are unable to do this- when we actuate the option they're logged off and we are also disconnected, apparently because the QS application is closed at their end. If we try a Log Off from the Start Menu, we are also disconnected and cannot reconnect, presumably for the same reason. If we try to Switch User the connection remains but our view of the screen is locked out until the user logs back in.

Is there a way, using Teamviewer QuickSupport 14, to log a user off without losing connection so that the remote operator can then log in?