Considering the last post "Quantum Weirdness No More" dated 10 Aug 21, this is the updated diagram where interference occurs at a point \(180^o\) and not beyond \(180^o\).
The third polarizer pushes photons beyond the \(180^o\) phase, they do not interfere and cancel completely and hence a brighter region.
Complete cancellation occurs only at the point \(180^o\) phase, with an incident beam at \(0^o\) phase.
