If a rocket silo is set from manual mode to automatic, the previous rocket inventory is moved to the trash slots and inserters cannot insert items into it anymore.
But if the rocket is full (e.g. with space platform foundations) and one of the connected inserter has still a few items in its hand (e.g. stack inserter, stack size 12, hand content 6 platform foundations), this items will be placed into the rocket in automatic mode.
Given one space platform has requested inserters, the free slots in the rocket will be filled with inserters by robots, so the rocket in automatic mode has a mixture of space foundations and inserters as cargo.
The minimum payload for inserters is not reached and the space platform foundations cannot be removed by robots, so the platform is stuck.
Does it happen always, once, or sometimes?
Always
[Genhis][2.0.21] Inserters place items into automatic mode rocket, item mixing and rocket stuck
Re: [Genhis][2.0.21] Inserters place items into automatic mode rocket, item mixing and rocket stuck
Thanks for the report. In 2.0.24, inserters won't be allowed to drop their hand into rocket silos in "automatic requests" mode unless the item matches the request.