Same as MC-181778, but using a legitimate setup. Original reporter, comment if you want ownership of this ticket.

With 20w18a and onward aiming to make redstone more intuitive mechanically and visually, there still exists one remaining quirk: redstone wire, when carrying power and pointing upwards, does not neccessarily provide power in that direction.

See the attached screenshots - it can be seen that a signal strength of 1 pointing into a powerable block will provide power to said block, yet an equivalent setup for it to point into a powerable mechanism from below does not turn it on.