OUTLOOK 2000

I have a user who experienced an interesing problem with Outlook 2000:

She forwarded a message that she received earlier using the send-on-behalf-of function. When she first received the message she modified it by deleting a specific paragraph and then forwarded it on to several users. When the recipients received the message the paragraph was still evident and looked as though the message was never modified. However, in the Sent folder she could see that the paragraph was indeed deleted. Any suggestions as to why this happened?