Trial Spawners not spawning custom mob [SOLVED]

Trial spawner recognizes the mob and everything, even showing it's model inside the spawner itself. going into survival mode causes it to activate like normal, but doesnt spawn any mob. Spawning the mob via spawn eggs/normal mob spawners works perfectly fine btw, so its only the trial spawners that arent working. Having the trial spawner spawn a base game mob (i tried with hoglins) works fine with the provided settings so its not an issue with that either.
(also sorry if the image doesnt show up, im hosting it on imgur and it still shows up broken in the message preview) 

Is there any fix to this? i can also provide the settings of the custom mob/trial spawner if needed