I am trying to use =VLOOKUP(I14,T:U,2)

When I14 is the time value 19:50 or 0.826388888888889

My table T:U has all the times from 00:00 to 23:55 in a sorted list of 5
minute intervals

The vlookup is in a list with other values which work e.g. =vlookup(I13,T:U,2)

It is only the one time value that returns the wrong result the value it
returns is that associated with 19:45 does anyone know why this might be the
case?

I also tried to use the Match function and this also returns the wrong value.

I have looked on lots of sites and this problem seems to be unique can
anyone help