When the dark prismarine block is placed at eye level with nothing underneath it, you are able to walk halfway through it and then begin to take suffocation damage. Found this when building a roof out of the slabs and stairs too, except it is only fazing through the solid block, not any of the other variants. This is only happening on occasion though, not every time it is tried.
Comments 2
Cleaning up old tickets: This ticket had been set to 'Awaiting Response', but has not received a response from the reporter (~3 months+) so is being closed as Incomplete. If you feel this is still a valid issue then please comment, or create a new ticket following the Issue Guidelines which includes steps to reproduce the problem.
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I tried to replicate this a few times but was unable to, do you have any specific steps you noticed when the issue occurred?