Can gross negligence by counsel amounting to "virtual abandonment" constitute an "extraordinary circumstance" that justifies relief under Rule 60(b)(6)?

"[G]ross negligence by counsel amounting to virtual abandonment can be an extraordinary circumstance that justifies [relief under] Rule 60(b)(6)." Mackey v. Hoffman, 682 F.3d 1247, 1251 (9th Cir.2012) (alteration omitted) (quoting Cmty. Dental Servs. v. Tani, 282 F.3d 1164, 116971 (9th Cir.2002) ). In such circumstances, "a petitioner may be excused from the consequences of his attorney's conduct where that conduct effectively severs the principal-agent relationship." Foley v. Biter, 793 F.3d 998, 1002 (9th Cir.2015).