As stated before, this could happen if your using any kind of hacks or you have turned something off in your settings. Also, I think this also may be a glitch.
In this picture it appears to be night inside the hostile mobs section of the mob dome. I'm not sure why it appears that way for you, but that is a client-side issue that is likely caused by using a modified client. Also, there is supposed to be water in the entrances to the mob dome. It keeps getting removed. I assume there is an exploit that allows players to somehow get rid of water in the spawn. If anyone can figure out how the water is disappearing, PM me and I'll give you a free rank upgrade. EDIT: Glitch found by @Nuggets and patched
i remember there was a glitch at warp question (the thing under spawn) where you could get infinite lava, not sure if its fixed yet :/
I get this same issue to i reported it to @MinetimeSupport twice lol the portal was working without water