Philippines pursuing Sabah claim against Malaysia as ‘we have not forgotten’, says Locsin
https://www.scmp.com/week-asia/politics/article/3101844/why-philippines-reviving-its-dispute-malaysia-over-sabah
At glance, it seems to be arrogance of Philippines. But, if Sabah becomes a part of Philippines, Philippines can treat south part of South China Sea as its territory. It means there wouldn't be any reason to allow China to govern islands on the sea.
So, to stop China's expansionism, it's important for South East Asian countries to cooperate with each other.
