+1 on issue here... Plugins are
AutoBroadcast, Backpacks, BluePrintShare, ChestStacks, CraftingController, Deathnotes, FurnaceSplitter, Gathermanager, InfoPanel, itemskinrandomizer, nightlantern, placeholderAPI, Quicksmelt, Removertool, Simpleloot, Skins, Stackmultiplier, stacksizecontroller, time of day ...
The F1 Kill, Quitgame, restart game, login, spawn confirmed working on my server in an instance or two.
will try the Plugin by "The Real Toxic" if issue perissts.