Redstone torch transmits power through 1-block air gap

A redstone torch is powering a block below even though there is a 1-block air gap between them.

There is a 1-block gap between the torch and the lower block, filled with glass as shown in the screenshot. even if the blocks in between are replaced with air, the behavior is the same.

There is a 1-block gap between the torch and the lower block, filled with glass as shown in the screenshot.
However, the lower block still receives redstone power and activates the piston/dropper setup, but the glowstone lamp does not receive power.

This should not happen because the air gap should prevent power transmission.