Let’s remember, too, that a huge percentage of East Asian students have been full-pay, and there has been an economic slowdown happening for several years there. The decline may reflect fewer overseas Chinese in Malaysia/Singapore (in some fundamental ways, the same place) willing to take this particularly expensive educational option, especially as compared to something like Yale-NUS. That plus a one-year dip in South Korean admissions due to the SAT fiasco could explain the whole thing.
I think Harvard is demonstrably committed to maintaining at least the current level of international admissions. But the national composition of those admissions is going to change over time. Over the past few decades, Asian students have largely replaced Europeans and Latin Americans. When I was in college 40 years ago, there were a few people from Korea, Hong Kong, and Taiwan, and a Laotian in my entryway, but I can remember meeting exactly one South Asian student: none at my own university, but once when I was visiting Harvard I had breakfast at the same table as Benazir Bhutto. I suspect now there is increasing interest in students from Africa and the Middle East / Asia Minor.