If amd put orders to Navi 12 and Navi 14 now They have to wait 6 months Until They will get first chips from TSMC... 8 think that They will prefer putting more orders to Navi 10 and Ryzen 3000 chips at this moment... so that is most likely the reason we don`t see any new small Navi rumours at this moment. Only production samples around, but no production capasity from TSMC to produce them...
Heh! Intel could screw amd and every other company by making big order to TSMC by themselves nobody else would not have any production for long time
Ofcourse that would be really bad thing to happen, but Intel has money to do it. It would take at least half year to full year to other companies to move production to Samsung.
But you don't know when they bought the wafers - probably back when the lead time was still shorter. The news about a 6 month lead time is for capacity being purchased today, which would affect chips planned for launch in Q1/Q2 of 2020.