So I’m having a problem with stair stepping in the mesh when I use bendy bones. I found you can correct it using the corrective-smooth modifier but it’s not perfect. I’ve included two screenshots of my dolphin in the rest and posed positions and another in in the posed position with corrective-smooth.
Rest Position:
Pose Position:
With corrective-smooth:
I know corrective smooth fixes this but I want to know why it’s happening (and how to avoid it in the first place).
So I figured out the problem. The stair stepping is caused by the stepping of the bendy bones and actually lines up with them if you look closely. Also, I had the armature modifier coming after the subdivision modifier and this stepping shows up if you don’t have the armature modifier above the subdivision modifier. I changed it to have the armature displacing the mesh before the subdivision modifier and that fixed it.
Technically the mesh is still getting displaced in steps as is shown in the last image in my post but you don’t see it if you put the armature with the bendy bones before the subdivision modifier. Also, this stepping may cause a problem on denser meshes that don’t use a subdivision modifier, but I doubt the developer will decide to fix that 
Here is an image of the fixed model in pose position:
As you can see there is no stair stepping now (Also you can see I increased the number of bendy bone segments to mitigate stair stepping).
Yep, you need more subdivisions - and usually it is good practice to have armature first, then subdiv.
Yes I believe that was the problem.
