TITLE: GCN CIRCULAR NUMBER: 21361 SUBJECT: Fermi GBM trigger 522334209/170721535 is not a GRB DATE: 17/07/23 00:28:16 GMT FROM: Oliver J Roberts at USRA/NASA O.J. Roberts (USRA) reports on behalf of the Fermi GBM Team: "The Fermi Gamma-ray Burst Monitor (GBM) trigger 522334209/170721535 at 12:50:04.518 UT on 21 July 2017, tentatively classified as a GRB, is in fact not due to a GRB. This trigger is due to local particles."