No, in your case the box comprises several characters just like mine. It's just not the single decoded character that the scope is displaying in the box, but also the ' ' marks around that character. The size of the box is too small to display 'F' so it just just displays as much of it as it can 'F then a red dot.
If you had the scope display the characters as HEX instead of ASCII, then it would want to show 0x46 in the box. That is 4 characters of stuff, if the box is too small it might show 0x4 then a little red dot. If the box was a little bigger, then it would should 0x46 with no red dot. If you expand the timebase so the box gets bigger, all the characters will fit and the red dot goes away.
It's really not a flaw. The font for displaying the characters is not a fixed space font, so the character F is wider than a 1