@TheJoker, what version of Camtasia do you have? I have seen bugs similar to what you describe when double byte characters were mixed with single byte characters in callouts. That bug should have been fixed in version 9.0.4. The current version is 9.1.0, which is a free update for everyone with 9.x. Please make sure you are on the latest version.
If you already have version 9.1.0 and you are still experiencing the issue, please submit a ticket for our Technical Support staff at https://support.techsmith.com and someone will follow up with you by email to help troubleshoot further.