VLOOKUP
can take up to 4 parameters, with the 4th being the match type.
By default, the match type is TRUE
(or 1
) meaning 'approximate' match. This is what is messing up your results.
You need to specify the match type of FALSE
(or 0
) for the formula to perform exact matches:
=VLOOKUP(A2,'Form Responses 1'!B$2:D,3,0)
Or,
=VLOOKUP(A2,'Form Responses 1'!B$2:D,3,FALSE)