GP is correct, but it doesn’t matter much. They were referring to daily key, not the EphID (RPI in the Apple/google spec).

DP3T specifies that SK _t = H( SK _{t-1} ). In that design, you share the daily key from when you started to become infectious, and then the subsequent ones can be computed. Then you go into quarantine, stop being infectious, and (see spec) create a new random daily key going forward (or delete the app).

In the A/G proposal, daily keys can’t be correlated, and you share the daily key for each day you were infectious.

The end result seems pretty much the same for me.