[RCU] Opening attachements display mismatched error

Hi,

I noticed after my upgrade to I think 0.9n, opening attachments like JPG or PDF gave this message,

"WARNING! This attachment is suspicious because its type doesn't match the type declared in the message. If you do not trust the sender, you shouldn't open it in the browser because it may contain malicious contents.

Expected: image/jpeg(.jpg); found: application/octet-stream(.bin)"

Would somebody know how this could be caused, and if I could avoid this message? Perhaps this was caused by misconfiguration in my RC installation?

Thanks, S