only stereolocant present implies actual locant position if ambiguous

[IngvarLa]

I came across (8aS)-Methyl-hexahydropyrrolo[1,2-a]pyrazine-1,4-dione in US20230301994A9 which should be
(8aS)-8a-Methyl-hexahydropyrrolo[1,2-a]pyrazine-1,4-dione
In the first case Opsin warns that the name is ambiguous and proceed to place the methyl group on N2. While the name is bad, I think the locant for the methyl group is implied to be C8a in cases like this. Any thoughts.

CN1C([C@H]2N(C(C1)=O)CCC2)=O (8aS)-Methyl-hexahydropyrrolo[1,2-a]pyrazine-1,4-dione
C[C@@]12N(C(CNC1=O)=O)CCC2 (8aS)-8a-Methyl-hexahydropyrrolo[1,2-a]pyrazine-1,4-dione