We are also having this issue. We have Outlook 2013 and Outlook 2016 on Exchange 2013. Our Outlook 2016 is on a 2012 R2 RDS server. We are seeing this issue in a shared mailbox environment. We do not see this issue on individual mailboxes.
Cannot disable Eset integration because we have e-mail addresses that are not through Exchange server and need Outlook protected. What other solution are available?