Same result with frequency:

=IFERROR(INDEX(FREQUENCY(IF(B2:K2="","",COLUMN(B2:K2)-COLUMN(B2)+1),LOOKUP(2,1/(B2:K2<>0),COLUMN(B2:K2)-COLUMN(B2)+1)),2),COUNT(B2:K2))

...confirmed by pressing CTRL+SHIFT+ENTER to activate the array, not just ENTER. You will know the array is active when you see curly braces { } appear around your formula. If you do not CTRL+SHIFT+ENTER you will get an error or a clearly incorrect answer. Press F2 on that cell and try again.