Today while tiding up the area close to the BS chamber I noticed that there was same air leaking from a pipe between BS and NM2 chamber (see attached picture).

As soon as I touched the pipe tying to tight it better, it came off, loosing a lot of air. With the help of Matteo, Fujii and Ishizaki-san we managed to reconnect and tight it. Now the pipe seems well attached but there is still some leakege even if it is smaller than it was before. 

It has to be checked by an expert as soon as possible.