Steps to Reproduce

• Create an issue TESTONE-1 and include the comment "foo" inside the issue for the first comment:
  

• Navigating to the Advanced Search, using the following parameter should not display the issue TESTONE-1:

  comment !~ "foo"
  

  

• However, navigating back to the issue page, try to add the second comment "bar" into the issue:
  

• This issue is reproducible using the same parameter in the Advanced Search JQL whereby you can see that TESTONE-1 is displayed, ignoring the original condition of the JQL:
  

Workaround

• Create a filter such as

  comment~foo

  , which will return all the foo comments. Save it as foo comments

• Create a new filter as

  filter!= "foo comments"

  . This will exclude all issues from the previous filter and the desired results will be returned.