With Excavation 1.4 installed breaking blocks even without activating the Excavation key is quite often not dropping the block and leaving a ghost block that returns to what it was when you update the block space or try to place something there as well.

This happened using a diamond pickaxe, Did a small amount of testing and discovered: Breaking ore or sandstone was fine. Breaking an anvil, leaves, or glass panes caused the issue. I had first noticed an issue with mekanism pipes and assumed that was a Mekanism issue, until I tested just Forge and Mekanism and discovered the issue was not present. Adding only Excavation to the pack caused the issue. Excavation 1.3b does not cause this issue.

Were you on a server? I can't reproduce this on singleplayer

It is in singleplayer.

I can reproduce this every time I launch the game. I just did further testing, breaking any block in creative mode seems to cause the issue. In survival breaking anything that can be broken by hand, such as a wood log, even if you do saw with an Axe cause the issue. Breaking dirt with a shovel did not cause the issue, breaking it by hand did cause the issue. Breaking leaves by hand causes the issue, with shears there is no issue.

I normally play with the GDLauncher, however I setup a profile in the Twitch launcher and reproduced the issue. Here is the crash report for that. edit The crash is from the other bug I reported.

Here's a short video of this happening. It also ends with a crash after I press the grave key.

This should be fixed now. I had some typos and I kinda feel like an idiot

This should be fixed now. I had some typos and I kinda feel like an idiot

Just updated and tested on my install, working flawlessly! Thanks for the quick updates!