Not sure if you are aware, but if you use 'README.md' in a jira comment, it will automagically converted to an url to....https://gitcareer.com/
At first I did not understand, but then somebody told me that 'readme.md' is actually a domain... so apparently you are checking strings with a dot in it against domains?
And readme.md is the redirected to https://gitcareer.com/ :-(
You have to 'unlink' the string to show it as 'README.md' again..
Wat about NOT following redirects by default?