No, its a different thing than MC-1263. Mine is getting unpowered when a pressure plate is unpowerig it when at the same time a redstone line is powering it. Its two different things. And the redstone line must be five or longer for it to work. Just try it yourself.
Yeah, I think end portals should be placable in th end. Good for mapmakers too.
Maybe a new mod/admin its also possible toplace blocks above the portal and block it with a block protection plugin.