Let's be honest, I spend my free time trying to find bugs and errors in apps. I may be harsh on them sometimes but I usually provide good feedbacks as a result of this hobby.
The following bug is not found in my free-time bug searching sessions. :) I was really trying to check-in before my THY flight but the app failed me yet again.
The bug was easily reproducable so I recorded the following:
All you have to do is enter your information and press the Checkin button more than 1 time quickly.
The app cannot be used and nothing can be clicked after this point. The funny thing is that after this, the back button also becomes blocked.
Lesson to be learned: Be careful when you override the behavior of the back button. Try to use system provided components like Fragments for it.