A report from Sean Ross Sapp of Fightful claims that Matt Riddle's recent call-up to the main roster was more than a simple transfer from one roster to another - it impacted the situations of multiple NXT performers.
Due to the travel ban that prevented Riddle's NXT Tag Team title partner Pete Dunne from flying to the United States for an indefinite amount of time, Riddle was placed into a brief feud with Malcolm Bivens' tag team Indus Shera, while holding out for the chance that Dunne could be cleared to return to the States to resume the partnership.
When the decision was made to have Riddle lose the belts, it was determined that Indus Shera wasn't ready for the spot of carrying the titles, and the two were removed from TV. It was decided that Imperium was better equipped to reign as champions, so the angle was drafted for Timothy Thatcher to fill in as Riddle's temporary partner for the eventual switch.
As for Dunne, Sapp's report says that there are no concrete plans for wrestlers stuck overseas, but it's possible that he could appear for NXT UK, if they get the show up and running.