NSight incorrectly displays doubles expression result

I have two Kernel variables, both are type double

At a breakpoint, I look at each value:

utm1 = 1080209.5800000001
utm2 = 1080209.4800000000

the next line includes an expression:

(utm1 - utm2)

when I select the expression and look at the value, NSight shows

utm1 - utm2 = 429496320.00000000

It appears to be misinterpreting the type?

you may want to file a bug at developer.nvidia.com