Quest does not work?

Hi, I play on WOTLK Lordaeron server (x1) and I was doing a quest "Powering our defenses" (https://classic.wowhead.com/quest=84...g-our-defenses) but it does not work properly. I need to place a crystal near a rune stone and defend it for 1 min from the scourge. But when I place it nothing is happening, so no scourge is spawned, no timer, nothing. I can even place many crystals and they are just standing for several minutes and then disappear. I checked a video, so I do it in the right way. Can you help me?

Thank you in advance

yes, it is bugged: https://www.warmane.com/bugtracker/report/82773

Next time to find out if a quest is bugged or not you can go here: https://www.warmane.com/bugtracker and use search box

Thanks, I got it.