It's looking like the "G1 Reunion" TFCon in LA last week was just a one-off special event, not their annual American convention.... as they have just announced their "2019" America Convention being in October (the usual part of the year), in Washington DC. (actually in Virginia, some distance from the territory of Washington of DC)

October 25-27 2019, at the Hyatt Regency in Reston, Virginia.