Starting from 0.16.x, when a chest is blocked:

• Hoppers should be able to push items into it but they can't.
• Hoppers should be able to pull items from it but they can't.
• Droppers should be able to insert items into it but they can't.

This could be WAI but is nonetheless a regression. All of the above used to work prior to 0.16 and were consistent with the Java edition, and now these things are version disparities. This is very inconvenient for compacting contraptions.