"Obsidian generator" replaces redstone by cobblestone with a wrong data value

Confirmed. Lava (+ water) replaces redstone by cobblestone with a wrong data value.

There is no cobblestone with a data value of 3. Invalid.

That will be the end of the obsidian generator...

Obsidian generator still works (14w20b):
Place redstonedust, then water that it wont destroy it, so 8 blocks away.
Then place lava 3 blocks away from the redstone dust.

Obsidian is created.

Invalid? If Minecraft is doing this automatically, it's not invalid. It's a bug.

Still working i just tested it

Confirmed for 14w21b.

EDIT 2: I need to read the description more carefully. Redstone with power level 3?!? You don't use powered redstone in redstone generators. It's UNPOWERED redstone. Powered redstone just is destroyed, allowing the lava to reach the water and break the machine. I'll leave in the stuff I said before I realized that important detail:

You don't need to place the water 8 blocks away, you place it beside the redstone with a pit below it so it flows straight down into the pit instead of sideways. I haven't build one in ages and the water physics seem different now. It flows sideways even with a pit below it if you have 2 water sources in a row now. Putting a water source every 2nd block seems to fix that. Now I'm wondering if the last time I built one was on the xbox.

And just to be clear, once I got it built (on 14w21b) the obsidian generator worked as normal. I'm sure there's still a bug, but only if you build it wrong. You shouldn't be getting cobblestone of any type of course. You should be getting obsidian. Of course no matter how wrong you build it you shouldn't be getting anything with the "texture missing" texture, so there's a bug somewhere.

EDIT: added a screenshot of my setup (minus the lava, which should be placed 2 blocks above the ground since falling lava flows 1 square further (4 instead of 3)).

https://bugs.mojang.com/browse/MC-58365

Not exactly the same... but "cancel" to be duplicate; it confirmed in version 14w25b (I recommend upgrading to this version). No obsidian generated, directly generates nothing or coblestone (by position as water and lava).

I did tests on 14w25b. Again, obsidian generators do not work in this version.
I add screenshots in:
https://bugs.mojang.com/browse/MC-58365