So.
Since in-game the Looping and Trigger Effects of AssetBundles are labelled starting with 1.
And Lua itself is also 1-based, for the purposes of table arrays and math.random (the latter being more relevant here).
Why is obj.AssetBundle.playTriggerEffect (and I assume the rest of the AssetBundles section) 0-based?
Ya done goofed... You bunch of sillies.