The property 'transition' no longer working?

based on the example here, Transitions - PowerShell Universal
i’ve built a number of dashboard pages with collapsible section which are still working fine, but i get lots of notifications like this :
Cannot process argument transformation on parameter ‘Pages’. Cannot create object of type “PowerShellUniversal.DashboardPage”. The property ‘transition’ was not found for the ‘PowerShellUniversal.DashboardPage’ object.

I’ve created a test page with just the sample from the documentation, and it does not load at all with the same error. is there something wrong with the support of new-UDTransitions now?

running powershell universal 4.1.4.