AS4 5.1.2(b)

This section states:

"This profile supports the One-Way/Pull MEP. When sending a Receipt for this MEP, a Receiving MSH conforming to this profile MAY bundle the Receipt with
any other ebMS message header (including an eb:PullRequest signal) or message body"

Bundling is about combining sub-element of eb:Messaging, such as UserMessage and different types of SignalMessages. It is not clear to me how a receipt could be bundled with a message body.

Perhaps what is meant is:

"This profile supports the One-Way/Pull MEP. When sending a Receipt for this MEP, a Receiving MSH conforming to this profile MAY bundle the SignalMessage containing the Receipt with
another SignalMessage including an eb:PullRequest signal or a UserMessage sent to the same MSH as the received message was pulled from."

Actually, it would be useful to constrain this further to the first option (bundling with a pull request), and specifically to bundling the receipt with an pullrequest addressing the same MPC as the pulled message was pulled from.