Drowned mob grinder no longer working, horse disappears from leashed position, and lingering xp orbs 1.16.100

Issue 1.  Drowned farm no longer working.  I created a drowned farm in Survival that worked fine until the update.  Since the update, mobs do not seem to spawn.

 

Issue 2.  I had a horse that was leashed to a post (the horse was named) and upon return to the post, only the leash remained on the post.

 

Issue 3.  Xp orbs occasionally linger/follow me without actually proving xp while I have equipment with mending equipped.