Castets and Sémillon on the same vine

How is this possible? In 2019, we top-grafted this plot of Sémillon with Castets and Mancin. Here, the graft took well (Castets), but the vine was poorly de-suckered to remove the Sémillon regrowth. As a result, the vine yields a crop of both grape varieties at the same time. This simply requires us to do two separate passes for harvest. Whilst we wait to re-graft the remaining Sémillon vines once and for all.