The strange event where some Filipino nationals, followers of a defunct Malaysian Sultanate, and Malaysia is an interesting one. It is a relatively minor affair considering that the Philippines has stated that they will not guarantee the protection of the Filipinos in the beleaguered town that the Malaysian security forces. This isn't surprising, as this conflict is occurring in Malaysian territory and the Filipinos are the aggressors, they are also acting without consent, tacit or otherwise, of the Filipino government. However, though this is minor, this could be the rumblings of greater discord between the Philippines and Malaysia. If this is, then this would be a golden opportunity for China.
The United States has been fostering greater military cooperation between the Philippines and Malaysia in it's efforts to contain China in the South Pacific. Malaysia is especially a key player considering that the Malaysia borders the straight of Malacca, where 90% of all East Asian oil shipments pass through. If the US can keep Malaysia on the US side of the alliance ledger than it will have a much easier time containing China. If not, then containment becomes much more difficult, if not impossible. As for the Philippines, it is also part of a key series of relationships the US has been developing to ensure that it's naval security ring remains unbroken. Along with Taiwan and the Japanese island, it forms the bulwark of the Pacific military ring that the US will use to leverage it's military power against a militarily ascendant China.
China currently starts out this geopolitical game in a disadvantageous position. The US has strong military relationships with Japan, Korea, and the Philippines, a much larger, more sophisticated, better trained, and spread out Navy supplemented by both South Korea and Japan, which have their own robust Navies. Whereas China's navy is relatively bottled up due to geographic, and hence more vulnerable to attack, the US navy enjoys freedom of movement. This is one of the reasons why China is developing anti-carrier weaponry. They know they are at a disadvantaged position and are seeking whatever means to level the playing field.
If this small ethnic spat grows, then this could be the opportunity China needs. Right now the south east pacific nations are wary of China due to competing claims on the island in the South China sea. China has recently been very belligerent in this regard and, given some of the rules of geopolitics, the island nations have cozied up to the United States recently. After all, if you have to be under an umbrella of a powerful nation, better that it be a powerful nation that is far away. If the US has to make a difficult choice on who it will support, then China could use this opportunity to wrest an ally away from US influence. But that is assuming that this ethnic conflict grows into something larger, and that remains to be seen.