The example should tag emails from Redmine with two tags: a fixed "redmine" and a dynamic one based on the project name. However, the configuration does something different: It tags ALL emails with the "redmine" tag and additionally tags emails with the "X-Redmine-Project" header with its content. The reason for tagging all emails is that a missing header is considered having an empty value and the pattern matches an empty string.
The fix is to ensure that the pattern does not match an empty string.
The example should tag emails from Redmine with two tags: a fixed "redmine" and a dynamic one based on the project name. However, the configuration does something different: It tags ALL emails with the "redmine" tag and additionally tags emails with the "X-Redmine-Project" header with its content. The reason for tagging all emails is that a missing header is considered having an empty value and the pattern matches an empty string.
The fix is to ensure that the pattern does not match an empty string.