"Open skies"-type agreements, of which the US-South Korea ASA is one example, do include 6th freedom rights (in the USA-Korea agreement, this is expressed as the right for designated South Korean carriers to carry passengers and cargo "from points behind the Republic of Korea via the Republic of Korea and intermediate points to a point or points in the United States and beyond" and vice-versa).

The problem is the 8th freedom (consecutive cabotage), on the assumptions that Palau is treated as the US for these purposes. In that case, however, I would have thought that a 24 hrs stopover would solve the problem: it would then be, in substance, an open-jaw 'return' (such as, eg, SFO-ICN-LAX).