I have the same issue
Hi @computerglobe,
This issue only seems to occur for a few users. I haven't been able to reproduce it and I can't think of how to fix it.
If you would be willing to let me access your installation, that would be extremely helpful.
If so, please submit this form with as much detail as possible.
Hey guys, I still haven't forgotten about this.
Here is something that I thought of.
If you installation directory has the wrong ownership, your osTicket / osTicket Awesome will still mostly work, but it can create unexpected issues like this one. Therefore, you should make sure that your installation folder has the correct owner.
For example, I accidentally uploaded my new osTicket Awesome installation as the root user:

The support directory should be owned by the same user and group that my main website runs under. In my case the user should be rede and the group should be psacln.
To fix the ownership I simply ran this:
# chown -R rede:psacln support
Please let me know if this helps or not.
I am still having this issue. For now i have just replaced the php code for the logo with the default for OSTicket so that it just uses fpdf/print-logo.png for the logo and that works 100%.
So my guess is it has something to do with something in /osta/php/functions.php that does not agree with my setup. Something around the use of the custom logo.