We have a small workgroup, using Outlook locally on our PCs - no server.   i am on MS Office Professional Plus 2013.  The others in our group are on the same or on 2010.  Sometimes when i send a meeting request, the person receives a complete request.  For one individual (and this has now spread to at least two other people), the request shows up as a blank email.  The subject line is correct, but there is nothing in the body of the email - and it shows up as an email, not a meeting request.

in addition, i have started getting responses from other people without the meeting icon on the email list.  they get the meeting request ok, and respond appropriately, but instead of seeing the meeting icon, the email shows up as a 'normal' email.  this does not occur with everyone.

Any suggestions on why this is happening, and how to solve it would be helpful - i cannot count on meeting requests to act correctly, and it is very frustrating.