Why canceling is silent
Instagram does not notify the other account that a follow request was sent and then withdrawn -- the request simply disappears from their pending list without any record visible to them, which is different from unfollowing someone you are already approved to follow.
Requested vs. actually following
A "Requested" status only applies to private accounts, since public accounts do not require approval -- tapping "Follow" on a public profile follows them immediately with no request stage to cancel in the first place.
Frequently Asked Questions
Will the person know I requested to follow them and then canceled?
No, Instagram does not send any notification for either the original request or a canceled one -- from their side, nothing ever appeared to request in the first place once it is canceled before they respond.
What if they already accepted before I could cancel?
If the request was already accepted, you are now following them, and canceling is no longer available -- you would need to unfollow instead, which is a different action with its own visibility.