Thanks Strannik, yep I think our problem is the same as yours. Water blown in under tiles.

Yep, the water marks are aligned to the splitter area.
After some googling. I have decided to extend the downpipe and connect directly to the gutter below.

Hi All,

We have a roof leak near a downpipe spreader. The leak has never dripped but there are wet spots on the gyprock inside.
I cannot locate any cracked…