First of all.. Planchets that are missing an area aren't clipped. They are actually Incomplete. When the planchets were being punched out from the stock sheet they would sometimes not advance foward correctly so the next planchet would be cut to close to the previous cut hole. The call them clipped but they aren't. Fake ones are made where someone actually alters a coin by cutting off some metal. One answer to your question.. They should have the same curve as another same denomination.
A clipped planchet should have a "cut & shear" edge on the part that is missing. Any design features near the clip should taper away toward the edge that is missing.
I see that it looks like the rim is thick. But I still think it is weakness. The strike didn't fill in the collar area of the coin.
Just adding another link specifically for curved clips that shows an edge: https://www.error-ref.com/_curved_clips_/
Clips as they are commonly called are actually incomplete planchet errors. There are many kinds, curved, straight, etc. one way to tell us to place the same type of coin into the missing area on curved ones.
This is not always true. The clip can change shape due to metal flow. In fact, straight clips can wind up looking curved, and curved clips can appear straight. They can also become warped.
This! There are some really complicated clips out there!! Understanding how different shapes will be impacted by the upset mill (i.e., turning Type 1 blanks into Type 2 planchets), is key. Usually, my eyes go to where the rim runs into the clip (gap). Those rims will dovetail in from the fields. There are exceptions, of course, such as a coin sheared apart by the collar die, or an incomplete punched planchet coming apart when the coin is struck, but note that those are much scarcer.
