Satellite signal interrupts viewing each night at 10

I have the following installation; one satellite 90 cm dish with 3 LNB, D1, D2 and INT 5 (IS19), the 3 LNB cables go to a switch

and from there to a splitter to two cables, one for upstairs TV Samsung smart and dish TV S7070r and one downstairs to

Samsung smart and dish TV S8200.

This installation works with no problems switching between satellites on both dish TV boxes, however when I watch BVN on the

D2 satellite a signal coming through interrupts viewing for a short time, 30 sec to 2 min approx.

There is no interruption when I watch anything on the D1 satellite.

This happens at 10 every night, I have contacted dish TV but they say that they can not replicate this problem.

Anyone knows who sends the signal and how to fix this problem?