The news is… there is no news. 
On august 30. I received an e-mail from Appellofunk (the dealer where I bought the triplexer) stating: “if you like please open the TriPlexer to see what happend.”
So that’s what I did and that same day I sent them pictures of the inside of the triplexer showing at least 2 burned (probably more) SMD capacitors.
Since then, no more news.
E-mail between Germany (Apellofunk) and the US (Inrad) must be going by boat I guess…
Pretty frustrating!