Sebastian Grygiel

In my case the fps drop occurs when crossing chunks. As long as I stay on the same chunk I get stable fps, when I move to different chunk I get ~20fps for a second or two.

MC-48114 clearly states that the command doesn't work for any block with an underscore within its name. It points out in an example that it doesn't work for lapis_ore. The error message clearly says that it began to parse lapis_ore as json and cannot find key-value separator (:).

This is different issue. I can confirm that this command works with lapis_ore or several other blocks with an underscore within its name. The issue occurs only with unpowered_comparator (out of tested blocks). The error message also says something different - it expects a json string but it doesn't start parsing it. It says that it expects { which is nowhere to be found.

Please, point me to a part that makes the issues similar apart from the command used and the fact that unpowered_comparator actually contains an underscore and this has nothing to do with it as, at least in 14w28b, the command fill ~ ~1 ~ ~ ~1 ~ minecraft:unpowered_repeater 3 replace minecraft:diamond_block works - the problem only occurs with unpowered_comparator.

Somebody attached a duplicate link to a different issue. I don't know how to remove the link.

The issue described there is affecting all blocks with underscore and it simply cannot find them.

This issue affects unpowered_comparator and not, for example, unpowered_repeater. The error message is completely different.