I'm trying to filter an out of box widget "Overall Devices Backed Up vs. Not Backed Up" with custom property No_Backup with a value of No. Says it is an incorrect query condition.
Your top screenshot shows the custom property name is No_Backup however your second screenshot shows a query condition referencing a different property name Backup_Job with Backup_Job='No' -- you would need to change that to No_Backup = 'No'
I'm seeing the same issue when changing to the correct property name.
Nodes.CustomProperties.No_Backup LIKE 'NO'