Air Burst conversion

[Ukase]

For whatever reason, when you have an attuned Air Burst, you cannot convert into another Ranged AoE set. Air Burst is available from 10 to 50. There are sets that should be possible to convert into, but for whatever reason, this one, when attuned won't convert, except out of category. 

I grasp that some sets will only convert within categories that are in the same range, but that doesn't seem to be the case here. Annihilation, while available from 20 to 50 should be an easy conversion from Air Burst. I mean, there's so many sets in this category, I don't grasp why Air Burst won't work. Now, a leveled Air Burst will convert. But not the attuned version. 

 

[Hedgefund2]

This has been brought up several times in bugs.

 

Here's the most plausible reason for "why".