my test were showing me that I had to match sequence setting fps with export setting fps in Premiere so that Encore's interpretation of video and audio clips matched same time duration
i see your clip properties of 50 fps, sequence settings of 50 fps, lower thirds of 25 fps and exporting to PAL of 25 fps
i was simulating in another thread with 59.94 fps and exporting to 29.97 fps and almost never achieving same video and audio clip length match in Encore, until I exported the same fps as my Premiere sequence