GET /rest/api/2/field sometimes returns 403 --- authenticated as plugin
Since 2019-06-02T03:11:40.740+0300 until 2019-06-02T03:14:11.335+0300 30 requests to /rest/api/2/field authenticated as our plugin (Structure) resulted in 403 Forbidden. Then they began returning valid results.
Given other similar cases (ACJIRA-1838, ACJIRA-1839) we suspect that it might be in fact related to some internal 503. In such cases, the resource should also return 503.