In-Game scripts can transfer items to un-connected cargo containers.
Before you ask, yes i have tried this and it still works with no mods at all.
The script in question is TIM (Taledens inventory manager, Updated version) https://steamcommunity.com/sharedfiles/filedetails/?id=1268188438
I copied to grids to a different world and it behaved itself again...
Issue: In-Game scripts seem to be able to transfer items from cargo container to cargo container without being connected via conveyors.