I think you might've introduced a slight bug when you moved the asset loading code into AllocateGameAssets(). You brought the SubArena() allocation into the function, but then the rest of the copied code allocates memory from the passed in main transient arena, not the dedicated asset sub-arena.
Thanks! I do not have the code in front of me at the moment but we can take a look at this on the next stream. It is likely that I made a mistake here - I find that when I am on stream I tend to make bad copy-and-paste errors, perhaps because talking uses up some part of my brain that would normally look for linguistic replacements or something :(
This is just a friendly reminder for you to look into this bug on the next stream. Unfortunately timezone difficulties mean I can't remind you in realtime on the live stream.