Blocks above chest stops comp readings

if a comparator signal causes a block to be pushed above the chest its “watching” it turns the comparator off until the block is removed. also if another block is placed above the chest at the same time the comparator will stop reading the chest entirely (even after both blocks are removed, and requires a block update to continue to read the chest. NOTE: the piston (sticky) doesn't need to be powered by the comparator directly, i found this bug with the signal going comparator → redstone dust → observer → piston, but as shown it also appears in comparator → piston.