Conditional logic does two things. It hides the field from view and disables the field so that it is not submitted. The conditional logic is seeing that the field should be shown and enabled and removing the disabled state in the JavaScript for conditional logic.
If you want this field to be visible even though it cannot be edited, then I don’t think there is any solution. The only think I can think of is to make it read only as well.
If you can get away with removing the field completely once it’s filled in you can return false from your filter and this will remove the field from display. Another option is that you can actually change the field type in your filter and change it to a message field, if you do this then there will be no field do edit.
