Why do we get an unrecognized permission error from the API on the permission check request?

[Konstantin Virolainen]

Since our first release, we have the com.almworks.jira.structure__access-to-structure-cloud permission in the app descriptor.

We check this permission using the /rest/api/3/permissions/check endpoint.

{"globalPermissions":["ADMINISTER","SYSTEM_ADMIN","com.almworks.jira.structure__access-to-structure-cloud"],"projectPermissions":[],"accountId":"xxx"}

For some reason, sometimes we get 400 Bad Request error as a response.

{"errorMessages":[],"errors":{"com.almworks.jira.structure__access-to-structure-cloud":"Unrecognized permission"}}

What's wrong?