Couple more data points, had recent experience of this with a couple of friends; all originally thru ticketed HNL-LHR (as AA108) in F.

Crediting to AA, I only received mileage for a direct HNL-LHR. No credit for the stop in LAX.

Crediting to BA, my friends had two different experiences.
Friend 1: Credited HNL-LHR, as 0TP. After chasing BAEC three times, who were refusing to believe such a ticket was possible, it was eventually re-credited as 240 TP.
Friend 2: Downgraded at the gate, cabin oversold. Credited as HNL-LAX and LAX-LHR, received 350 TP. Oddly, BA must have seen this as a re-ticket...

In the other direction all three of us saw the credits as LHR-LAX LAX-HNL, likely because of the enforced stop to clear Customs.