your color expression can only be valid at the detailed level, not at the total level. At the total level, the field [Day Utilization" may return multiple results, which turns the value to NULL and the whole expression is invalid. In this case, I'm guessing, the background color of the first row is adopted for the total.
I'd recommend to make your calculation valid at the total level and hopefully it resolve the issue.
I'd also recommend to add the default color value that should be used if both conditions are false. Currently, it returns NULL as the default. It might also cause the same issue.
Upgrade your Qlik skills at the Masters Summit for Qlik - coming to Prague this April!