Riddle of the Deep not showing walkway puzzle.

Some rounds I skip doing the puzzle so I could upgrade and repair cause of low mob numbers but when I go into the portal later, nothing is there, just a big empty room and I'm stuck and can't do anything.

Don't know if would make a difference, but did you try stepping on each of the first "stones" to see if any of them light up. Maybe the path is there but it isn't lighting up correctly.

It would be a slight bit of extra details that might help. Of course this would only mean something if the problem happens for you again.

No stones at all, Just the room without the puzzle at all. So I can't even see it to do it. I can run to the other side and press the valve but it won't let me and the portal doesn't work. Luckily, I am able to beat it while afking, or else I would lose every time this happens :(

and yah, it has happened again, 5 times to be exact. Since doing it solo with the low mobs, I don't have to do it at all, but I like to try it once in a while cause it's kind of fun and the water gets annoying :P but it stinks when I go in and then bam no puzzle to even try at all!

Yea I've also had this issue.

We've had a few reports of this issue and we'll look into it to see if we can't find what's going on.