Outlook in Citrix Font Randomly Changes

I’m using Outlook 2003 client in a Citrix environment. Several users have noticed that randomly emails that they send out have different fonts and sizes. An example would be the first part of the email is written in 12pt. Times New Roman, but then halfway through a paragraph in the middle of a sentence it reverts to 10pt Arial. The user is not copying or pasting anything into the email. Message format is HTML and cannot be changed, and stationary is set to . Anyone have any thoughts on why this could be happening or any possible fixes. We’ve also reset the users Citrix profile with no difference. Thanks