Help with FilterExpression

We have a custom record that I am searching on in SuiteScript. I am filtering on a date in the custom record and a custom field on the customer record. The customer record is a parent to the custom record. I have tried a couple of instances of filtering based on a filterExpression and standard filter both shown below. I keep getting join errors when running in debugger.

When run I get "An nlobjSearchFilter contains an invalid join ID, or is not in proper syntax: custentity_cust_corp_dash_account"

CUSTRECORD_CR_CUSTOMERNAME1 is a field that is populated from the customer list so I've tried both the field name (which works in other scripts I have used) and "Customer" as the ID for the Join. Both return the same errors. DashAccount is a variable named elsewhere in the script.