Rooting for underdogs!
That post-test skates report was published in mid-September? Machine translated excerpt:
ETA:This time we had a little delay in the preparation of Jon and Tiffany, - says coach Svetlana Lvovna Alekseeva. - It was due to Jon's illness. In the summer, he again fell ill with *********. Moreover, for the second time. Therefore, the guys' trip to England to stage a production with Christopher Dean was postponed all the time. Finally, at the end of July, they went there [England to work with Dean on their FD]...
No reason given for Z/G's withdrawal from Skate America (Morozov/Bagin are the other originally assigned Russian dance team):
Российский дуэт Тиффани Загорски/Джонатан Гурейро, выступающий в танцах на льду, не примет участия в первом этапе Гран-при по фигурному катанию - Skate America, РИА Новости Спорт, 13.10.2021