When uploading a video that has a resolution of 720x480 or 720x576 the Size and Position filter does not cover the whole image. It crops it at the bottom instead of filling up the whole image.
720x480 is 3:2 not 16:9 and 720x576 is 5:4 not 4:3
As far as the size/position filter did you set your project to the right size/ratio before importing your video? And was this behavior the same in 18.9? Is this a display issue(IE does the filter work properly if you enter the correct numbers despite displaying wrong?)
Please try setting your video mode before importing the files and bringing them in after that, it looks like it is highlighting an area that matches the ratio it thinks the videos are.
That is incorrect because that assumes pixels are square. There is this thing called sample aspect ratio and where 720x480 can be 16:9 in what is called anamorphic widescreen.