So, I tried loading Trinity Worlds in 2.50, and this happens:
It goes back to normal when I close ZC and reopen it, whether or not I delete the file. So probably minor, but something worth reporting I suppose.
EDIT: It reappears if I exit to main menu after playing.
Trinity is not the only old quest this happens on. I had this happen when I played Link's Giant Adventure on an older 2.50 build. Annoying, but only cosmetical