MTRX Studio SPQ HP filter ignored except for L,C,R

[alphastar]

We recently had our system tuned via SPQ in two 7.1.4 studios - 1) Avid MTRX w/ SPQ and 2) Avid MTRX Studio (16ch. SPQ built-in).

Both studios have HDX cards as well as a connected Pro Tools Sync X, and use identical amps and speakers/monitors via the MTRX or MTRX/Studio DA. The MTRX Studio is using 118/256 SPQ filters only on the DA outputs.

Testing is conducted with Pro Tools 2022.5 in 7.1.4 out to Dolby Atmos Renderer to MTRX Studio > DigiLink 1-32 to DA.

When a HP or LP filter is applied to any output besides the L,C,R channels, there is no change to the DA output. However, the Ls or Rs (for example) have 12 parametric filters applied at different points, and if the EQ is removed for the channel a change is heard. If all 12 filters are removed (manually deleted) and only a single HP filter is added, no change is heard.

If the same tests are conducted using L,C,R channels, the change is immediate. Also deleting any filter results in a brief silence and change in the audio.

Tried with DADman 5.5.0 build 2 as well as 5.6.2 Beta (build 13b) w/ latest Avid MTRX Studio firmware (1.0.1.3, I believe), macOS Monterey 12.3.1 on Mac Pro 2019.

Both .dmprof and .dms were created from scratch (not imported).

Is this by design? Has anyone else seen or heard of this?

Help please?!

With Thanks