Is there a place I could put it as a feature request then?
Yes, but I believe it'd need a code change in the client, and it should be easy to fix.
It also affects Hungarian (HU) layout.
I can confirm it with armor stands.
Hey, I liked that "feature" and it's now fixed... 😛/gamerule mobGriefing nope
If matters, I can confirm it on 1.7.10 too, also running the server with ">file.txt" outputs the same text:
2014-07-19 17:25:12,132 ERROR Error processing element Queue: CLASS_NOT_FOUND
2014-07-19 17:25:12,158 ERROR Unable to locate appender ServerGuiConsole for logger
It also affects 14w26c with NVidia GeForce GTX 650 graphics card.
Disabling OpenGL solves the problem for me as well.
It looks like they fixed it by preventing spawners if there is a mob already in the exact same spot. (Tested in 1.6.2 demo.)
(It only spawns around 10 ticks if there is a mob while I set 1 tick.)
And it doesn't try to spawn on peaceful at all,
Sorry, then propably my computer was slow, now it's working for me too.
Almost, for me, only the redstone block turns into an other pushed block. (And not becomes invisible.)
When I place a second redstone block the first one shows up sometimes. But maybe this issue is because I have a bit slow computer (for running Minecraft).
Here is my world in the attachments.
Why do you think it is modded? I downloaded the new launcher, logged in and played the demo version.
Thanks.