Changing the name of an Actor Component code class in a project results in any existing Blueprints that derive from code classes that use that Actor Component to not display the Actor Component's properties in the Details panel. Any new Blueprints that are created after the Actor Component class' name is changed will continue to work fine. Renaming the Actor Component property in any code class that uses it and building the project will allow existing Blueprints to again show the properties for the Actor Component.
No. The same behavior occurred in 4.19.2
Nothing appears for the component in the Details panel.
The properties for the Actor Component are still shown in the Details panel as they were prior to renaming the parent Actor Component class.
Change the name of the Actor Component property from step 4 in Visual Studio (this can be done the same way the class name was changed previously) and build the project again.
There's no existing public thread on this issue, so head over to AnswerHub just mention UE-67850 in the post.