If a player dies with the Splash Potion of Invisibility, when they respawn, they are still invisible, and the timer is gone, so it is an infinate invisibility.
This is a MAJOR problem for pvp servers!!! This was the worse addition mojang has brought to this game..... What were they thinking not disabling pvp or ANY interaction when using these new invisible potions?
I'm sure there will be plugins that allow you to disable the use of invisibility potions... So don't worry.
This issue should be fixed in the new build that will come out soon.https://bukkit.atlassian.net/browse/BUKKIT-2673
Dev builds aren't going to work perfectly, there are always bugs. I learned this the hard way when 2 worlds on my server were overwritten when I was dumb and used the first 1.3 dev build on my server without backing up the worlds. ALWAYS back up your worlds before using a dev build.