AA seems to have finally figured out that JAL considers I to be a higher fare class than X now.
As of March 2022, X now earns 70% of miles flown and I earns 100% + a 25% cabin bonus.
That's great news. I sent another message to AA regarding this problem in December, but got no response. It would be nice if they apply this change retroactively since I received 47% less LP than I should have received. However, it will be very difficult to convince someone who took months to figure such a simple thing out to do it. I have been already disappointed by the recent AAdvantage program update, I will likely not bother.