Conditional formating not working when referring to cells on other tab

Hi guys. I have a spreadsheet with tons of calculations that we use to check for data quality. I was cleaning it up a little bit because all of the #DIV/0-style errors were making it hard to see the calculations.

For the entire spreadsheet, I used the below conditional formula to get rid of the errors and only display the calculations. However, one calculation has a term which refers to a cell on another tab and I am pretty sure that this is casing the function not to work. Instead of leaving a blank like all of the other calculations, it just shows 0.00%. I know this because I used a cell on the same tab in place of the cell on the other tab, and the conditional function worked perfectly. This is the equation:

=IF(B20=" "," ",=IF(B20=" "," ",(B20/'Series consistency, Net Assets'!C20)))

I've tried the third term both with and within parantheses and it doesn't work. It just displays 0.00%.

Does anybody have any ideas as to how this can be corrected?

Thank you so much!