Blue Series 3-Way - holding up paddle jumps to max brightness instead of ramping dim

I have a Blue Series 3-way circuit w/ AUX switch and with a neutral. Switch is in smart bulb mode and set to dimmer output. Load is Phillips Hue bulbs which are grouped and bound to the Inovelli. Firmware v

On/Off taps work fine (and the bulbs correctly do the quick transition on/off).
Holding down correctly ramps the dim down until you release.
But holding up causes it to jump instantaneously to max brightness (no dimming behavior and no on/off transition).

I have at least a couple dozen Inovellis, including several other multi-way circuits, and none experience this issue. I’ve had 2 electricians check the wiring.

Any ideas?

What is your local dimming speed set to?

Local dimming speed is set to 127 (default). Settings should be all default other than the multiway and smart bulb settings mentioned.

Try changing it off of default to something else and see if it has effect. Otherwise try doing a reset on that switch. Also make sure you’re on the latest firmware.

There is nothing in the wiring that will affect dimming so no need for electricians. The switch controls dimming levels and speed through its firmware.

There are some bulbs/fixtures that may have compatibility issues but they normally present with flickering not instant upwards dimming. That’s why I’m leaning towards that firmware setting.

I was never able to root cause this (and a reset didn’t work, switch is on 2.14 firmware).

But coincidentally, I decided to rebuild my zigbee network and move from ZHA to Zigbee2MQTT for unrelated reasons and the switch now works just fine!