If there are walls close to the ghast it will suffocate. Try keeping it in an open space with a lead to a fence post.
Yep me too and I’m playing on survival and it’s supper frustrating that I have to keep making new ones because they have disappeared a few times now
I was having the same issue and then watched it die because it turned facing the wall and then just suffocated. I made it like a helicopter landing pad with a fence post in the middle and used a lead. Hasn’t dies since I did that.