Sounds like exuberant exercising to me. I don't have budgies, but since this forum is pretty quiet, I thought I'd jump in. You've mentioned elsewhere that they don't leave their cages, so I'm presuming they're feeling the need for some exercise.
Since you had to separate them 6 months ago for fighting, it seems wise to reintroduce them outside either bird's cage (territory). Do you have a room in which they might safely spend some out-of-cage time under your supervision? Or could you give them a cage to share in which they could fly even a little? As little as 4' wide would let them take a few flaps and would give each room to stay out of the other's way. The tiny tiny cages too often sold as appropriate for budgies are often the cause for aggression
My best, Paca