Good evening Jaap and welcome to the Events Calendar Support forum!
Thank you for reaching out to us.
We are sorry to hear about the titles looking ugly while using QTranslate-X.
Unfortunately, we do not support QTranslate-X or Polylang as multi-lingual solutions for now.
The only plugin we do support is WPML for that purpose.
With that in mind, I believe that this is simply a matter of adding the QTranslate filters to the Ticket titles.
I wish I had a better answer for you, but for now it’s the best one I have.
Have a good weekend,
Geoff B.