OctaMic XTC as Aux Device – TotalMix 2.10 a8 randomly changes 48V/PAD

Hi,

I have a problem with my OctaMic XTC as aux device.
Every few minutes the XTC changes settings on its own: channel 1 suddenly gets
+48V and PAD, and the Digital Routing blocks MADI 33-40 and 41-48 get switched
around. Happens a lot when loading snapshots but also just during normal work.

Setup: UFX+ on a Mac Studio (macOS 26), TotalMix 2.10 alpha 8. MADI ring
optical: UFX+ -> M-32 Pro DA -> M-32 Pro AD -> OctaMic XTC -> back to UFX+.
Only the XTC is set up as aux device (ID 1, bank MADI 9-16), the M-32s are not
MIDI controlled. XTC firmware is USB 47 / DSP 26, I even re-flashed it with the
new flash tool 3.83 – no change, the problem was there before the re-flash too.
I also tried switching off MIDI Ctrl Thru on the XTC, no difference.

First I thought a snapshot had 48V stored on that channel, but I checked the
workspace files, they are clean, no 48V/PAD stored anywhere on those channels.
So I put MIDI Monitor on Port 3 and watched. Normally I see this:

every ~300 ms: F0 00 20 0D 69 01 12 F7
every ~2.6 s: F0 00 20 0D 69 01 20 00 00 70 7F 01 00 70 7F ... F7 (40 bytes)

The short one stops when I quit TotalMix, so it looks like the XTC answering
the aux polling. But every few minutes I catch a broken frame like this:
F0 00 20 0D 69 01 20 00 00 70 7F 01 00 70 7F 02 00 70 12 F7

The dump stops after channel 2 and ends with the tail of the short message,
and right after that MIDI Monitor logs a bunch of "Invalid" 2-3 byte fragments
(00 12 7F, 00 1C 74, 00 7F F7, 00 07 00 and so on). The timing of the two
messages drifts against each other so they collide every few minutes, which
matches exactly how often the XTC screws up its settings.

I also sent a test note to Port 3 to check for a ring echo – it does not come
back. So the broken frames really come from the XTC itself, it seems to push
its polling replies into the middle of its own dumps. And since the Digital
Routing changes too (aux control can't even do routing), something on the
receive side of the XTC gets confused as well.

Is this known? I have full MIDI Monitor captures if needed.

Frank