PIP on OpenATV

I am using OpenATV with my VU+ Solo 4K, and PIP works fine with two channels from different tuners(DVB-S and DVB-T).
But, when I try to do PIP with two channels from the same satellite (not same transponder) I can see only one channel.
Is there a problem or I need to configure something?
Thanks!

Tuner setup:
1st DVB-S2 tuner Positioner
2nd DVB-S2 tuner: loopthrough to 1st
3rd DVB-T2/C dual tuner

Only one feed from motor to first tuner.

- - - Updated - - -

Just to clarify sth:
when I watch one DVB-S2 service I can stream(or record) another from the same satellite so tuners are working as they should

Another clarification:
apparently I have not a good configuration of the tuners, as I cannot use tuner B for streaming.

Any help for the correct configuration of the second DVB-S2 tuner with only one line?

Thanks!

Forget the FBC for one moment.
I just want to use two simple DVB-S2 tuners with one cable.
With the GB Quad I had previously I could do this with the internal loopthrough.
Isn't it available in VU+ Solo 4k?

I am resurrecting this thread as I've recently got other equipment:
1 x Inverto Black Unicable Quad 40mm LNB 2 Legacy Ports 0,2dB + 1 Splitter
1 x TBS Brand TBS5925 USB DVB-S2 TV Box,Unique USB TV Box supports VCM,CCM,ACM and 32APSK

Can you please, help me the configuration so I get the most from all the tuners?

Thanks!

My setup:
1 motorized dish
1 cable going to 1 receiver
1 x Inverto Black Unicable Quad 40mm LNB 2 Legacy Ports 0,2dB + 1 Splitter
1 x TBS Brand TBS5925 USB DVB-S2 TV Box,Unique USB TV Box supports VCM,CCM,ACM and 32APSK

The config I need is for my VU+ solo 4k. How to set first and second internal DVB-S2 tuners and then how to set TBS?

Thanks!