If I enter a full name of a user like "This is user.name" the username is sometimes renderes as "This is" and sometimes as "This is user.name".This is inconsistent and the username should renderes as entered. It seems, that sometimes special filters are thrown at the full name and some times not. I run a fresh installed version of osTicket 1.9.3. The german string are translated by myself and I use not any language pack.
Somewhere in the settings is the Name Format (can't look where exactly right now). Did you try to change that setting or can you tell me what the current value of that setting?
The value of "Default name formatting" is set to "First Last".If I change the name of the user to "This.is my name" It shows only "my name" instead of "This is" as shown above.
Try to set it to "As Entered" ;)
This works, as expected. Nevertheless, I think, this is only a work around. I think, this is a bug and should be fixed, because it's unexpected behaviour.
thread from 2014 and for an old version.