Bubbles when upside down

[emoreira]

Hi, I have a Dacor 900 + Pacer main second and Pacer XLE octopus. Both breath well.
I tried to use the XLE as main second, it works fine, however, when I'm upside down, or being horizontal and looking behind, I feel a bubble stream coming out the XLE when I'm not inhaling, this is when I'm exhaling or in the few seconds that I switch from inhaling to exhaling. This bubble stream stops as soon as I rise my head.
Is this a calibration problem ? How can I correctthis. Thanks in advanced.

 

[Fishpie]

You could try detuning the 2nd stage or flipping the seat.
.....loosen the locknut and screw in the oriface 1/8th turn, you can do this while the reg is pressurized.