You may see unexpected behaviour if you add required fields to your issue types being used by Avion. Please stick to the defaults for required fields. There is an Atlassian article outlining how to remove required fields here.
A common problem is that a field is not visible on an issue. For example – a custom field value, story sizes or even epic links. Jira can be a little tough to manage, but ultimately, you will need to seek out your issue type's "screen" configuration and add the field.
If you use complex workflow options in Jira — such as — restricting an issue's next status depending on the issue's current status, you will need to abide by these rules when changing story states in Avion. If you don't, you may miss changes or ultimately end up out of sync.
Unable to find "Story Points" custom field
If you are using a project that is not rooted in agile — i.e: not a Scrum or Kanban project in Jira, you are not able to use the Story Points field. Therefore, this will not be available to map to Avion's sizes.