This can happen if you're using Microsoft Outlook to forward bills into Lightyear. Outlook, by default, can send emails in a Rich Text Format, and this needs to be changed to Plain Text. Thankfully this is very straight forward.
When in Microsoft Outlook:
On the Tools menu, click Options, and then click Mail Format.
In Compose in this message format, click to select Plain Text, and then click OK.
Please Note: To send to certain recipients that use RTF format and others recipients that use plain text format, the sender must set the option for the recipient in either the Personal Address Book or the recipient's contact record.