OS X 10.11.2 El Capitan
The slides are freezing or overlapping for much longer than the set cross fade time. The preview is working as expected.
It happens on both my MacBook Pro and IMac
Sent from my iPhone
Please follow the below steps and check for the issue.
> Launch Lightroom
> Click on Lightroom > Preferences
> Click on Performance Tab
> Uncheck Use Display Processor
> Click on Ok
> Restart your machine
> Relaunch Lightroom and check for the issue
Let me know if this helps.