https://www.bilibili.com/video/BV1mm2wYrE33
1.20.1 has a bug with mechanical power. In the minecart assembly station, the complete large box that is restored from the assembled minecart to the block state will split into two normal small boxes. Both small boxes will contain the same items as the original large box.

Other dynamic devices can also use the same method to spawn items.

this is a dupe of #449 will require some kind of extensive integration in Create to be able to support and I am pretty sure if this is concern for you Create should have some tags that can be attached to blocks that contraptions are not supposed to move so that can be done.