There were a few bugs which crept into the last release. 3.0.1 should fix the issues with checkboxes, the export themes extension and timers. In 3.0.0 checkboxes were supposed to save their state when you tapped them but often didn't - and worse the code related to this sometimes caused the app to crash when updating a task. Hopefully all of these issues will be a thing of yesterday with 3.0.0.
As always if you have any issues with beorg please get in contact. You can do this via the Support link on beorg.app. To get involved in helping shape the future of beorg visit the forum - tap the forum link on beorg.app to get started.