When you first log in with QON_ID_1 and any IDENTITY_ID, we mark QON_ID_1 as the “identified” user ID. All subsequent calls to the identify() function using the same IDENTITY_ID with any internal QON_ID will reference the first user, QON_ID_1, from which identify() was called. This is why all purchases are linked to QON_ID_1.
In your case, the initial Qonversion user ID that initiated the “identity” process was QON_ID_1. As a result, any purchases made afterward will be attributed to this user ID rather than QON_ID_2.