Thought Slithering Dead Quest was bugged on map but I was wrong

I completed the slithering dead quest in act 3. It is completed according to my quest log. I talked to Servi and chose my reward (the 30% boost to elemental ailment threshold). I am pretty sure the buff is active. When I do the math, checking my elemental ailment threshold while unequipping my gear, the value is indeed half of my max life then x1.3. When I equip gear that has elemental threshold, it also is boosted to x1.3. So it appears to be working.

My issue is on my map, under Venom Crypts, the Venom Draught symbol is not crossed out entirely. The center vial is in yellow and the other two are grayed out. There does appear to be an X behind it, just not on the overall picture.

Please feel free to delete this post. Thank you.