External Hardware FX on Cubase 11 + MR816 Bug?

Hello all!
I´m using Cubase 11 Pro with a MR 816x audio interface on Windows 10.
I really hope I´m doing something wrong, I´ll explain:
1 - I created an external FX bus on Audio Connections (Send on Analog 5/6 out and Return on Analog 3/4 in) called Strymon (which is my external reverb)
2 - So from now on I just create an FX track, insert my strymon as External FX, and add a send on the track I want to send out for FX, normal procedure.
3 - Here comes the bizzar bit…My FX track only receives the signal back from my outboard gear if my MONITOR PHYSICAL KNOB on the MR816 is up. As if the 5/6 out is also controlled by the 1/2 main output level and not only by the send level on the track I´m sending the signal out. It makes no sense at all, that I need to have my Master Knob up (and I mean the physycal main out, not the fader on the stereo out track) in order to send the signal through 5/6 outs.
For me, it has something to do with the MR816 internal routing since there is a tab called audio hardware setup showing some digital control for my MR816 outs and maybe instead of sending the track through 5/6, it sends to 1/2 first and only then to 5/6? I really have no idea, this is freaking me out. To make things short, the Monitor Knob is preventing the signal to go out of 5/6!
Please tell me I´m doing something stupid, I would love to hear that! I made a video showing the issue here:
Video
Thanks!

After further tests using my small scarlett 2i4 I´ve detected that the issue is on the MR816X.
Master knob is preventing signal to go out of other physical outputs instead of only control 1/2 out
Since MR Editor closes whenever I open Cubase, I cannot have access to the MR816 routing inside cubase to verify this issue further more. Any ideas?