Beginner: Bending modifier is thickening object

[Anonymous]

Below is a capsule I was working on but, somehow throughout my edit, I accidentally flattened capsule and therefore caused it to lose the perfect circumference on the top of the capsule. (below is an image of the perfect top before and an image of the top after mistake) Is there a modifer or alternative to regain the circumference that was lost?

BEFORE

AFTER

[10DSpace]

If it's too late for undo, then you could turn off the top modifier in your stack.  The video shows you making the changes while in this top modifier.  So try disabling it and start again from there, this time without non uniform scaling shown in video.  I Don't know a way to regain circumference in this case.  Maybe someone else does.