Background Color manually

Hey, man  taylororiger 
I did test it again, I tried to recreate something that you have and used the exact same formula:

Measure = SWITCH(TRUE(),
ISBLANK(MAX('PE Relationship Detail'[Engagement Quality Reviewer Name]))&&MAX('PE Relationship Detail'[PE total fees])>500000,"yellow")

Applied to all columns and it works, the only thing that can be wrong is that make sure your blanks are actually blank, notice that in Power Query, blanks are "null". This won't appear in the Visual layer, however, make sure you can see it like that in power query:

You can replace it like this:

if you don't want to test and debug anything, you can add something like to your formula that checks either blank or empty string:

Measure = SWITCH(TRUE(),
(ISBLANK(MAX('PE Relationship Detail'[Engagement Quality Reviewer Name])) || MAX('PE Relationship Detail'[Engagement Quality Reviewer Name])="")&&MAX('PE Relationship Detail'[PE total fees])>500000,"yellow")

This should work even when you don't have your blank rows actually blank. 
So try this new formula first and lemme know.