I get error XYZ, the conversation is not displayed, the app crashes without any error message, ... Please consider this app as beta, I can't test all variations of WhatsApp backups out there.
However, if you don't mind and would like to improve the experience for all users you can send me the file you he problems with and I try my best to help you or fix errors. I understand a backup file contains a lot of personal information most users don't want to share, however debugging is much easier when you can reproduce the problem, so it would help me a lot. I am not interested in your personal data and will delete all the files you send me from my disks after the bugfix.
If you think you found a bug or he suggestions for future versions please report it here: Github Issue