Relates to MC-146862, MC-147710 and MC-156443.
The bug
As someone who uses arrow keys for movement, the hint for movement does not fit the names of all four keys on screen, causing them to go off the right.
How to fix
Either use the scrolling-left-and-right fix that UI buttons now use for exceedingly long text, or change the text over time as is the case with some advancements, as to display all of the text.
Other fix: make the box vertically bigger to include all the text; I'd actually prefer that over changing text, as the tutorials stay in place until completed, unlike advancements, which vanish after 4 seconds.