Having the same issue. I fell, broke my legs, crawled to water, drowned. I attempted to respawn, but it sat there waiting telling me to wait for about 15-20 minutes. I logged out, came back on another server, in the spot I had died, but in decent health, no broken legs, still hungry and thirsty as before.

Shortly thereafter someone PVPed me with an axe, I could not be killed. Then I wandered around "blurry" and bleeding for another 30 minutes or so, unable to even "respawn" to get rid of the problem. Other players have tried PVP'ing me, to no avail, they quickly give up.

I found that going to my inventory allows me to see the world a bit more clearly, at least enough to see other people or objects.

Still no resolution on this. Exited the game several times, been invincible for several hours. The downside to this is that I did attempt to fight back and won handily as I was invincible. Definitely a bad exploit for guys just out to win.

I would love to find some food, water, and bandages to patch myself up, see if I am still invincible... But I would rather just respawn and be subject to death as normal.

Also found that niether players nor zombies could kill me, as I basically ran a bleeding forest gump inland for several miles, attracting Z's and getting attacked several times in the process. Nothing can kill me, I am already dead.