I have an external form with First Name, Last Name, ... and I use API to create tickets.
I put some descriptive notes in Name of the submitter, so name looks like FirstName LastName (note).
Note is department for example.
When ticket is created that descriptive note is missing, it is just First Name, Last Name.
Is there some sort of a sanitization or osTicket just selects the name from DB according e-mail address (If e-mail address already exists in DB than it will use the name from DB not the name from API)?
API Name of the submitter
As a general comment, you probably should not be stuffing fields with information that doesn't pertain to the field that you are using.
What do you have this set to?
Admin panel -> Settings -> Users
Name Formatting:
If you change it to "As entered" does it display the additional information that you are stuffing in the name field?