
What I am trying to do:
If I have EDP info for one item. When I type into EDP input, CAT number and Description limit their dropdowns to select the same product.
If I have Cat number, EDP and Description limit their dropdowns to select the same product.
If I have Description, EDP and Cat number limit their dropdowns to select the same product.
How error occurred:

I first did the Cat combo box logic, which worked perfectly. But then I tired to do the same thing for EDP and I got that error
Box Logic:
For CAT combo box logic : If(Not(IsBlank(EDP.Selected.'EDP Number')),Filter('Products (custom)', 'Catalog Number' = EDP.Selected.'Catalog Number'),If(Not(IsBlank(DES.Selected.Description)),Filter('Products (custom)', 'Catalog Number' = DES.Selected.'Catalog Number'),'Products (custom)')) <-- this works perfectly
For EDP combo box logic : If(Not(IsBlank(CAT.Selected.'Catalog Number')),Filter('Products (custom)', 'EDP Number' = CAT.Selected.'EDP Number'),'Products (custom)')
If I need a different route:
Client wants to have dropdowns of their products that can be searched by EDP, Cat number or Description. Once any one of the three options is filled, the other ones either need to limit their dropdown or can autofill the other dropdowns.
Additional info:
After I solve this, Vendor will need to do the same thing, but it is from the Vendor table and not the Product table. So vendor input will have to limit the products as well. I don't know what the best route overall is here