Invisible ice?

[Lerno1]

I loaded up for a flight today, making sure Active Sky was ready to feed weather data as soon as the plane spawned, so I could see any possible ice accumulation and de-ice (I might be in the minority but de-icing in the sim is a novelty for me and I enjoy it when there's accumulation, which isn't very often). The weather was CAVOK and the outside air temperature was about 0 degrees C as reported by the datalink metar. The wings were completely spotless, and I decided to go ahead and takeoff normally without de-icing. Turns out it was a bad idea, and I couldn't takeoff. I tapped my joystick trigger thinking it was a brake issue, but the plane still would not accelerate much nor was it getting off the ground.

I usually use a lua script to indicate icing accumulation that makes up for the lack of visual icing in many addons, however I disabled it for the Challenger as visual ice on the ground is extremely obvious, and the plane's own ice detector works fine for in-flight accumulation. I decided to re-enable the lua script (top center diagram with red wings, showing severe icing) and turn on X-Plane's icing dataref indications, and it appears ice was indeed there:

I checked the wings to see if I had missed anything, but there still wasn't any indication of visual icing:

I thought maybe it was just harder to see on dark wings (though I have seen it before), so I switched to a livery with white wings and they still appeared spotless. Even the leading edge was clean, from what I see:

Am I missing something here? Is there any obvious icing visible in the above screenshots? Or is this a legitimate issue? To avert such disaster in the future I can just always load with clear and warm conditions to prevent ice accumulation from appearing, before reverting to real weather, but as mentioned I do enjoy the need to de-ice when I know there is accumulation.

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