Hi, thanks for reporting this, it does seem to be a bug with the plugin as the lantern tool does not properly get unequipped. You should be able to fix it by finding the function "CGMZ_DT_LanternTool.prototype.unequip" around line number 1510 and adding this line of code to it:
$cgmzTemp.stopUsingDungeonTool();
I will do some further testing and put an update out soon with this fix if it looks like it doesn't impact anything else.