That does look like a bug.
The unused 460,000 per-week comes out to 23.9M per annum, and at that juncture, I'd expect you to be able to move funds from transfer budget to wage bill and vice versa.
If you're playing with the 8.0.1 patch, please check the
FM'08 Bugs Forum. If this hasn't yet been posted - basically, if you can't find it on the first 3 pages or so - please post with screen shot, and, if you can, save-game so that SI can take a look.