Dirt disappearing from Support beams - bug?

[PhineasWynd 41]

Dirt keeps disappearing from where I'm placing it. It's supported by support beams so it doesn't fall, but is this intended? You can't fully support dirt?I place the dirt, so it looks like this:[imgur because the forum will only let me upload 162.67KB of images, what?]

 

As you can see, the dirt is disappearing steadily, and soon there might not be a roof.  ʕ•ᴥ•ʔSo my questions are: is this a bug, and how can I stop this happening / fix it?

 

Ninja Edit:Running on a local server, vanilla TFC with optifine and Somnia.I couldn't find anything on the wiki about dirt falling out from supports or anything.

[Skavaro 2]

Hey i observed that as well in my game. you can solve it by using a layer of planks under the dirt instead of the support beams. or a layer of cobble and support and so on.

 

On the problem itself - i think it happens when snow melts on grass and leaves back dirt - the dirt then falls down. if the blocks have grass on them they do not fall. But also not all block without grass do fall... it just happens randomly in my oppinion.

[PhineasWynd 41]

I've done some testing, and it seems that the blocks vanish when they turn from dirt to grass. I also can't place grass blocks in those places in creative mode at all, and I can place it anywhere else. I've 'fixed' this by making the ceiling stone, but still not sure if this is a bug or intended.

[Bioxx 796]

I don't have the code open atm but my guess with be that this is a product of some code meant to get rid of floating blocks. I'll try to remember to look at this in the future.