It's raining in the debug world

This might actually be an issue for the fire, the rain might distinguish it.

isn't that the old version of the debug world (gamemode 1, data values instead of block states) if so is it also the case with the new version (spectator only, block states instead of data values)

You are on 1.7.10 who doesn't have debug world, that's the reason why it's raining, look if it happens in the snapshots as well

Derp.
Opened 14w27c debug world in 1.7.10

14w27c? 🙂 I think you mean 14w27b 😉

Simply forget that ticket 😛