Hi Darryl! Thanks for your review
It can happen that your media freezes on screen for different reasons. Thinking about how to best help you on your editing process, we have created a tutorial which gives you guidance on how to proceed with drop zones to avoid such issues. Here you have the link for it: http://help.lenofx.com/specific-plugins/split-screen-transitions/
If this is doesn't help you or you have any other questions, please reach out to us at support@lenofx.com. I will be glad to assist.
All the best,