The wither skeleton spawner only works in the Nether Fortress Bounding Box and nowhere else. I was wondering if this could be adjusted to make it a bit more useful outside of the nether. Thank you.

Playing with the "Medieval Minecraft Modpack"

At least in my experience using Conjuring in a lot of different setups, I have definitely been able to spawn Wither Skeletons in areas outside of a Nether Fortress. You do of course have to make sure it is dark enough for them, if you can't get it to work it would be good to provide more context so we can go about reproducing your exact situation
Cheers

Have you been able to figure it out?

i am having a similar issue,

i have attached my setup and no wither skeletons are spawning

(latest attempt i used an egg to put wither into focus. not sure if that matters)

One more thing (sorry for spam)

My nephew has the same setup in a slightly bigger room that works with wither skeles

New observations
Created a spawner in another dim and it worked.
Nephews spawner stopped working.

Its acting like only 1 is allowed per server

Last comment i will make on this as i have given up getting it to work

It seems the "npc limit" has been hit as this does not work at the same time normal spawners dont work.
i /kill @e to remove the world of any hidden mobs and that still did not fix the issue

I found I was also having this issue, my problem was that I was using the Big Torch from Kibe which blocks mobs spawning in the dark, however the big torch still allows mobs to spawn on Cursed Dirt so thought it might not be a problem with the Conjurer which would've been nice 😄

Given that everbody who had problems seems to have fixed them and the original author hasn't responded in 2 months, I'll go ahead and close this as invalid, especially as every single time someone has reported a problem like this until now it was related to the Big Torch or a similar spawn-blocking gizmo
Cheers