It appeared for me on both AA.com and Google flights, so I'm not sure what happened. AA's search can be wonky. There does seem to be a problem with the Y fare on LAX-HND, AA.com seems to be only selling full-fare Y while Google prices cheaper because it is booking that segment in PE.

Separate thing, have you thought about connecting through JFK instead of LAX? I'd personally prefer that especially in J...avoids the AA narrowbody transcon, longer TPAC segment for sleeping (especially if in J), if in Y the JL seats are notably wider and pitch is almost as good as MCE, and if you are OWE you can select premium seats for free on JL that offer more pitch, better lounge facilities at JFK.