Jenne van den Boom

Skylight is 15 normally, the slimeblock acts like a leaf-block now. Sky-light will now diffuse, which means it gets darker over distance as the screenshot clearly shows since the value is 9 and not 15. Which wasn't noted in the patch notes and has game breaking experiences in normal slimeblock contraptions used in flying machines, like the ones used in the supported realms mini-game "missile wars" by cubehamster and sethbling. Why is it gamebreaking, because the current light engine cannot support it.

If you mean that it shows the backup and load for older versions, that's intended behavior. If you meant something else I can't work out from what you typed. The broken English makes it unable to reproduce the issue.

Can confirm, it wasn't listed in the changes of 18w07b while it worked fine in 18w07a.

The problem is that this isn't a tile, this is a commandblock with a datatag, not a tile entity. Same problem occurs when trying to do this with replacing 2 blocks next to eachother to a chest with a datatag to create a double chest with items inside them.

This is a bug, because we are able to replace blocks with blocks withouth a datatag and we're able to use the default replace with a datatag, but we're not able to replace blocks with blocks with a datatag. The parsing shows some weird results in the commandblock. This claims to be a bug.