Update draft-ietf-scitt-scrapi.md

draft-ietf-scitt-scrapi.md

@@ -284,7 +284,7 @@ returned it.
 If the `OperationID` is a valid URL, it MAY be included as a `Location` header in the HTTP response.
 
 Transparency Services MAY clean up old operation records to manage practical implementation concerns.
-The length of validity of the `OperationID` is Transparency Service specific but at minimum, the Transparency Service MUST maintain a record of every running or successful operation until at least one client has fetched the completed Receipt.
+The length of validity of the `OperationID` is Transparency Service specific, but at a minimum, the Transparency Service MUST maintain a record of every running or successful operation until at least one client has fetched the completed Receipt.
 
 The Transparency Service MAY include a `Retry-After` header in the HTTP response to help with polling.