Incremental compilation: Flawed for Rule Templates

Incremental compilation does not add new messages when a Rule Template is updated from being valid to being invalid. Full build with valid Rule Template passes; but Incremental Compilation with updated (and invalid) Rule Template does not lead to any "added" messages.

Updating a Rule Template from invalid to valid does however work. Full build with invalid Rule Template correctly returns error messages and Incremental Compilation with updated (and valid) Rule Template does lead to error message being removed.

Unit tests created (failing one @Ignored).