Issue explanation

When flying through ladders / vines / scaffolding whilst in creative mode, the player will just get stuck on them and has to exit flight to go down properly.

Mojira issue link

https://bugs.mojang.com/browse/MC-12829

Other

This issue is marked as unresolved and is claimed to be discovered back in Minecraft's redstone update but actually was a problem since Beta 1.8 in reality.

Not sure if thorium can fix this; anticheats may expect a certain movement speed through these blocks, even for creative players. Though I'm not sure how many anticheats are going to check movement speeds of flying players.

This can be set to be disabled by default and if client players want this then they can put it to enabled manually - it's a similar case towards MC-2071 where chat cancels out when players stand inside portals for example.