A similar thing happened with the F-22A Raptor. Pilots reported breathing difficulties, and for a while the "experts" were sure it was some exotic chemical toxi

A similar thing happened with the F-22A Raptor. Pilots reported breathing difficulties, and for a while the "experts" were sure it was some exotic chemical toxin in the air supply. After much investigation, it was confirmed as a combination of a faulty BRAG(Breathing Regulator & Anti-G) valve and poor breathing technique. The proximate physical condition is known as 'Acceleration Atelectasis' which is a lung issue resulting from the incorrect breathing technique under High-Gs. IMO a combination of fatigue, and a relatively high cabin altitude (8k feet) could easily account for the symptoms these crew are reporting.