Again, US DVD/Blu-ray players and displays are known to have issues with 25 or 50 field/frame content (SD or HD) - they’re generally not made with anything other than NTSC/film specs in mind (whereas European players have been NTSC ready since the DVD era).
Sorry, you are completely right… well, let’s take the 25/50fps to 23.976fps (or 24), and we will solve everything - or not? Even if there is some movie pieces in the PAL sources, they surely not have IVTC problems.