Regardless how the filters are set in the Class Viewer window, closing and reopening the window causes the filters to be reset to the default options.
No - this behavior exists in 4.15.3 Binary as well
Actors Only and Placeable Only are checked
The state of the Class Viewer is saved and Actors Only / Placeable Only are not checked
Head over to the existing Questions & Answers thread and let us know what's up.