Hello! I love the initiative of this app. In my experience I have found these bugs (at least with the application in Spanish):
1.- When you change the theme of the application (Example: from light to dark) the box and the entire application are blocked. In order to continue using the application, you have to exit and re-enter.
2.- When I try to open a .docx file from my personal Telegram channel, the first time it said "One moment please" or something like that. I left it for half an hour and it was still the same, so I closed it and left. The next day I tried again, but this time the application was blank. And from then on, the same thing always happens: the screen goes blank. In order to open a Telegram document, I have to open the document I want from the Telegram download folder from the Collabora application, and trying to guess which one it is.
I hope that this bugs gets fixed. Thank you and greetings!
EDIT: I forgot to say that theses bugs I have it in Android 6.0