While I was mining I found this weird wall that seems about 3 blocks tall and will hurt me for some reason. I can't get past it. Occasionally I'll slip through for a second and then when I go back i'll be stuck. Is this added my a mod? Very weird stuff.
Got the invisible wall on Ultimate 1.0.1. Two different users. One is below where xycraft tanks use to be but only one side. The other where a xycraft use to be. Pretty much most of the users have removed xycraft tanks due their buggy nature but the memory lingers on.
The odd thing is I can place blocks in the space I cannot cross and remove the blocks and then move freely though the invisible wall. However after a server restart it reappears.
I ran into the same issue on my mindcrack server in the nether setting up a blaze farm (this was back in January). If I targeted the block I could see its outline like I was getting ready to place a block. Couldn't move through it. I had to get rid of it by logging off/on then forcing the block to update on the server (I think I used a sticky piston to push a block into the invisible block.