The absence of the Browse Users Global Permission causes the WAS parameter to throw an error when it is used in the Advanced Search.

Steps to Reproduce

• Ensure that the Browse Users permission is set to at least a user / group. In this case, we just set it to Anyone:
  

• Run the following query below and it displays the results on the Issue Navigator just fine:
  

• After that, we removed the Browse Users Global Permission to no one:
  

• The following error will be thrown on the UI when the same JQL is being run on the Advanced Search:
  

Is there any explanation to why the Browse Users permission is mandatory when the WAS parameter needs to be used in JQL? What does the error mean?

A value provided by the function 'currentUser' is invalid for the field 'assignee'.