INVINCIBLE rare enemy BUG!!! (sabre spider)

i've posted something similar recently BUT THIS IS A RARE and you cannot end a map until you kill all rares, so i softlocked that map because the rare enemy is invincible and extremely buggy while going back and forth.
until this happened:

https://imagekit.io/tools/asset-public-link?detail=%7B%22name%22%3A%22aranha%20v2.mp4%22%2C%22type%22%3A%22video%2Fmp4%22%2C%22signedurl_expire%22%3A%222028-01-23T09%3A22%3A37.006Z%22%2C%22signedUrl%22%3A%22https%3A%2F%2Fmedia-hosting.imagekit.io%2F%2F7fe7a45e22ef4554%2Faranha%2520v2.mp4%3FExpires%3D1832232157%26Key-Pair-Id%3DK2ZIVPTIP2VGHC%26Signature%3DsBekD0hlh4VDCmxBh0qE2vHtkX5FNyxzEqPR38iGsQRvf0L7TMuFRlkd2OTbX1uAENZHAYUn1eDsIR1PMyBTWZzsemLVZpJOj-XLVxHZbHnPba3GAV~fs83BX~j02ylE3NsdTLFUwX9n2gIxiVKYap8zj6cn96U2WUJl26pPGChq67KmQJIrnTvyFJkdQFbC7nxm95ffxj-914UhkOaOvFr-3b~VPVneSXShBDpW4VdP3y4nOuw-GQf-ORdhAYw-MI8R505jmy1fvFEqJcHsinug3RmsNv7E0CkerrGRLSLIQOfQlzH3W6UJFJPHdPjYT8VDcCFDXtLwNLHIW3F7lQ__%22%7D

i oppened an essence AND THAT SPIDER BECOME THE ESSENCE MONSTER??? and no little monsters spawned from the essense, then that spider became mortal again, wtf is happening rn, so anyway pls fix

I had the same problem: invincible Sabre Spider as Essence-Mob (pre activation).
it was in the Act2 area Mastodon Badlans at me