Actually, your distribution not only has one mode it has three...it is
tri-modal and the MODE function is returning the first mode found which
also happens to start in the first cell.

I don't have time to work it out now but you may be able to construct
an array formula that counts the number of occurences of each value,
then counts the number of times the maximum count is hit. If the MAX
of the counts is = 1 then an if formula could show, "No Mode". If the
MAX of counts is 1 AND the count of MAXs is 1 then the IF statement
could print, "Multiple Modes", Else it could print the single mode.

Good luck.

- John