Danny, your account of the post August 1945 scene vividly points up the arbitrariness of military assignments in the Far East Theatre of War. For, despite your laudable description of the realities of the logistical issues involved, nonetheless troops had to stay out there while many of their European Theatre counterparts were being demobbed and of course grabbing the civilian jobs ahead of them.
I would suggest that was the trigger for the "Mutinies" (a word that conjures up lurid and bloodthirsty scenarios while the reality was rather more mundane and clerical in nature) rather than enforced idleness per se. Another issue was the varied attempts by the Colonial Powers (including the UK) to regain the territories lost to the Japanese and ironically using Japanese troops to help quell anti-colonial resistance in French and Dutch colonies. While no doubt they were required to obey such orders coming down the Chain of Command, these were somewhat at variance to the Atlantic Charter for which the War had supposedly been fought.
These were troops conscripted for the "duration" which might well be defined as expiring August 8th 1945, or very shortly thereafter. When some at last got home it was to a gloomy Post War Britain where everyone wanted nothing more than to forget about the War, which included those still returning from it. Hail the Conquering Hero! Not!