There is no firmware mid ramp blink, it’s hardware related and happens at the transition (or ”gear change” between the low and high range (or ”gear”).
It’s due the inacuracy of the MCU’s integrated DAC on the low end (offset), which create a mismatch between the top of the low range and bottom of the high range, resulting in a jump or a zigzag when it’s respectively higher or lower than it should be.
It’s amplified by the large op-amp compensation required with this boost IC which makes this transition more visible.
So this varies between lights, ones with low DAC offset will have a smooth transition, the ones with higher offset will have a more visible bump.
I could have used a lower HDR ratio, which would have lowered the effect of the DAC offset and lowered the required compensation value, making the transition less visible, but it would have been at the cost of a higher moonlight.
Probably a ratio of ~1:100 would have been better compromise than the 1:135 ratio used, but this is hardware set, it can’t be changed now.
Another option would have been to use 3 sense resistors like on the new FF Lume drivers, as the ratio for each gear is smaller the effect of the offset is smaller. But in the D3AA case it would still be a bit visible due to the boost IC used, and there would be 2 transitions instead of one, not sure it would have been better in this case. (Also it takes more space).