Having the same fare basis does not necessarily mean they are married segments, and married segments has no impact on FF accrual. Married segments means two segments where the availability is affect by the start and end point rather than just the individual flights.

For example, on this route, RJ may not be willing to sell a cheap I class business ticket on LHR-AMM or AMM-BKK so I0 for availability for those segments, but they are willing to sell an I class ticket for LHR-AMM-BKK so when you search for that you get I1 (or more) for each flight, but if you look for each flight alone you get I0 again.

All of this is just for info though and not relevant to the OP as regardless of how the fare is constructed and availability at the time of booking (married segments or not), they still credit as individual sectors in the class booked.