Thank you for reporting this issue.
If you could provide a few more details that would be great:
1. Is your iPhone setup to send crash reports to developers? If not it might be worth doing this temporarily so that I receive crash reports from beorg (see https://support.apple.com/en-us/HT202100 for details)
2. Does beorg always crash following the same set of steps you take in the app - or does it feel it crashes randomly?
3. If there are a set of steps to trigger a crash please provide details.
4. If you are able to, please try beorg with each org file individually to see if it is a specific org file which is causing the crash.
When I was looking into this I did notice a crash when beorg was updating its internal registry of tags that I hopefully have now fixed. It is possible that was the issue that caused the crashing behaviour. A fix for that will be in the next update in the next couple of weeks. If you do have any more information about what is specifically happening to you please add to this forum topic.
If you'd like to help test the upcoming update let me know and I'll send you a TestFlight invite. This build may fix your issue - and if not I should get a comprehensive report of any crashes and you'll get the ability to submit feedback from within the app.