Noodles on overhangs

Sorry for the topic, but it does very much look like a pile of spaghetti.
Even when printing with supports, I end up with lots of curled strands. They're stuck firmly together, but are of course really messy looking.
I'm printing ABS at 230°, heated bed drops from 120° first layer to 90°. I print in a big cardboard box to avoid the usual air movement warping, using a Mendel90 and Cura.
The prints turn out great, unless there's any kind of overhang, even a somewhat low angle one.

Admittedly, this is a 90° hovering surface, sitting on support walls. But the amount of curling and seemingly total randomness of them is odd.

Massive warping along the edge here (right side was "down" on the bed), despite partial support. Then suddenly it starts printing perfectly pretty halfways up.

Rightmost one was printed with the same settings, pretty as can be. Leftmost was printed with the messy surface hovering on supports.. even if I'd cut the support off straight, the entire bottom is a complete mess of spaghetti.

Any suggestions on this?

Just found out that this also happens with PLA.. not quite so badly, but even with the fan running at 100%.