Hi,
From the description, you mean emails sent by one employee end up in Junk folder in another user's mailbox, am I correct?
There are several reasons that could cause your emails to show in Junk folder. In Outlook, if we open the email from Junk folder, the InfoBar will tell you whether the message has been filtered out by the Outlook Junk E-mail filter or by something else. See:
If you see above message, it means you need to check your Junk Email settings in your Outlook. The InfoBar may also contain the following information:
"This message was marked as spam using a junk filter other than the Outlook Junk E-mail filter."
It means your messages are filtered by another scanner. Then you'll need to contact the support of the scanner to further look at the issue.
Please let me know what is displaying in your InfoBar so that we can narrow down the cause.
Regards,
Steve Fan
TechNet Community Support