There's a few things I would probably word differently, but this statement stood out to me:
"Upon using the Eye of Death, the Gravelord will leave a soul sign on the ground, indicating the place the item was used (1). The same soul sign will appear in 3 other players' worlds along with stronger black phantom style enemies (2), making their game harder."
1 - The Gravelord Soul Sign follows the exact location of the Gravelord Servant with an active Eye of Death. Unlike other signs, the Gravelord Sign will travel, refreshing its location every ~10 seconds. The way this is currently worded makes it sounds like the sign will appear wherever the Eye of Death was used, but it appears wherever the Servant is standing. If the Servant is moving around, the sign won't stay in one place for long.
2 - It's not actually known if the sign only appears in 3 worlds. There is speculation that the EoD seeks to infect a select number of worlds, but the sign itself appears to a wider group of people*. The sign appears to people within co-op range. I can personally confirm (and others can as well) being able to see a sign in my world without the infection taking place. It has happened several times to me, so the sign appearing "along with" gravelord black phantoms is definitely not a guarantee. If the sign does only appear to 3 people, whom are also supposed to be infected, then that means it's possible to successfully see the sign but the infection glitches or fails. (PS3 here, patch 1.05, if relevant)
*This is just speculation on my behalf, but this could explain all the "disasters are gone" messages people see. I think it's a poorly worded message, but not a glitch. Lots of people have reported that message without seeing infection, but I think the message has a broader implication. It's not that you were supposed to have the infection in your world, but that there *was* a sign somewhere in your world and it's no longer available due to the servant dying or quitting. Missing a gravelord sign can be a lot easier than missing an infection, and if the sign appears to more than just 3 people, that would explain why people see the message a lot.
I would guess that a more accurate message might be:
"The Gravelord sign has vanished. Disasters are gone if they occurred for you."