MWIF does not allow an Air Rebase over 9 controlled hexes by a FTR with range=3. It seems, as the most direct route (8 hexes) is "blocked" by a French hex, MWIF is not checking, that a longer route (9 hexes) is available.
The BA.65 stacked under the C.200 has the same behavior, it cannot rebase on the 6th hex in France, but both the BA.65 and C.200 can rebase on the 6th and 9th hex respectively if they go to Germany, for instance.