As you say it just seems to be a typo and doesn't affect the update, you get the correct new version.
It was suggested by a staff member that it was a typo when the new version was first released and had been corrected after a couple of hours, but your screenshot shows that it's still there for some.
How many are getting it and just why is another question, I suspect that not many people look that closely, don't notice it and just hit one of the buttons.
I've tried to replicate it myself by reinstalling v5.76 and then seeing what that message says, and it always shows the two different version numbers for me.