To be fair, there's no such thing as neutrality. If there's one, then its superficial neutrality. Indonesia, Malaysia, Singapore, Thailand and the Philippines formed ASEAN as a tool to contain Vietnam Communism during the cold war and Indonesia is the leading spearhead of that effort at the time. Does that mean Indonesia severed its ties to communist VietNam ? the answer is no. Even when Soeharto took power and eradicate the communists Indonesia still maintains formal diplomatic relationship with North VietNam and refuse to acknowledge South VietNam
and just like the Cold war Indonesia-VietNam experiment , Indonesia also use the same approach when it comes to China. Only this time Indonesia has a clear economic benefit of befriending China.
A slight peek on the Super Garuda Shield exercise would give you a hint on which side Indonesia is leaning to. You just won't let your Chief of armed forces doing joint training of a rival superpower without sending a message.
TNI chief Andika Perkasa in the Middle.
Chief of Indonesian navy, Adm.Yudo Margono also involved directly on the ground
The size and scope of this years iteration of Garuda shield is something Indo-Pacific watchers would have an eye into. Not only the direct involvement of top Indonesian military officers, but also the participation (under Jakarta's nod) of sensitive (for China) country in it.
JSDF soldier during Super Garuda Shield 2022. The first time the Japanese military set foot in Indonesia since 1941.
Not only the size, scope, participation would have Beijing irked, the scenario itself could be considered hostile. This is no exercise for anti-terrorist operation, rather a country-country high end combat.
with Warships drill, amphib assault, paradrop etc.
For comparison Indonesia had only done 2 exercise with the PLA, one in 2013 involving Army special forces and the other is a mere PASSEX with the PLAN after the Nanggala submarine accident.
So, maybe this would help answer @Ryder