I'm not 100% sure, but I think the two operate with slightly different tolerances. When I compare 4.0000000000001 and 4, the equality component says they are equal, and the function component says they are not. What values exactly are you giving?

If this is presenting a problem, you might take a look at the "near equality" operator in the function component - As I understand it it only compares up to 10 decimal places.