Having two branches in the same ``++if++`` structure with the same implementation is at best duplicate code, and at worst a coding error. If the same logic is truly needed for both instances, then they should be combined.
But this exception does not apply to ``++if++`` chains without ``++else++``-s when all branches have the same single line of code. In case of ``++if++`` chains with ``++else++``-s rule S3923 raises a bug.