EmailReadMessages marking emails as viewed in spite of "readonly=true"

[lauren@paradisepartners]

We are using Exchange as the email server. I'm connecting using EmailConnectPOP then using EmailReadMessages with "readonly=true". As soon as that step runs, the messages as viewed in an Outlook inbox change from not viewed to viewed. This didn't happen before switching servers to Exchange.

 

Could this be a fluke of Exchange? Or could it be because Outlook is using IMAP and the Email Plugin is connecting using POP?

 

Thanks,

Lauren Naslund