Maybe the side-by-side testing had the blubs too close together?
One on either side of a door? Maybe 3 to 4 feet?
Perhaps the incandescent was pulling them in,
and some of them flew over to the LED to check it out.?.
If bugs really like blue light, this chart seems to be showing,
that a white LED has a lot more blue emitted.
So, the LEDs would be worse than the incans?? Something is amiss here..
~~
Edit:
From what I've been able to find out, warmer colors=less bugs..
So, these 2700k LEDs might be a good choice..
Cree 9.5-Watt (65W) Soft White (2700K) BR30 Dimmable LED Flood Light Bulb (4-Pack)-BBR30-06527FLF-12DE26-1U110 at The Home Depot