No signal on transponders above 11700 - Octagon 4K SF8008 V3 Supreme Twin

I kindly request assistance in resolving an issue with the Octagon 4K SF8008 Supreme V3 Twin tuner (2x Si2166D (DVB-S2X)).

A few days ago, I purchased the specified receiver.

The receiver does not receive channels on higher frequencies. On transponders above 11700, there is no signal.

I have tried all available systems (OpenATV, etc.).

It looks as if it has a problem with the 22 kHz signal.

My satellite installation consists of a multiswitch and two quattro LNBs (Astra and Hotbird).

All other tuners in different rooms are working correctly.

What is very strange is that only on Define 7.0 software does the signal appear on transponders above 11700, but it comes after 1–2 seconds.

I've tried various LNB settings, from universal to manually defined. Diseq works correctly, switching between Astra and HotBird. The receiver is unable to properly control the 22 kHz signal.

Diseq works correctly and switches between Astra and Hotbird. However, the receiver is unable to properly control the 22 kHz signal.

I have a installation with a Terra MR-912L multiswitch, to which an antenna with two Televes Quattro LNBs is connected (Astra Diseq “a” and Hotbird Diseq “b”).

Regardless of the tuner configuration in OpenATV (universal LNB, manually defined oscillator values lof/l 9.75 GHz and lof/h 10.6 GHz), there is no signal on transponders above 11700 on both satellites.

However, when I run the receiver on DefineOS 7.0 software, everything works correctly.

I have checked the cables and the entire installation. If I connect a different receiver in this location, everything functions properly.

I have noticed that OpenATV uses kernel 4.4.43 while DefineOS uses kernel 4.4.176.