I was making an automatic sugarcane farm. I tested two different circuit types using dirt and redstone dust and when I tried doing the same thing with glass, it did not trigger the pistons. Here are the designs, denoted in text.
Design 1:
Observer Redstone dust
Piston Glass
Design 2:
Observer Redstone dust
Piston Glass Redstone dust
Redstone dust Glass Redstone dust
Glass Glass Redstone dust
Redstone dust Redstone dust Redstone dust
Glass is a non-solid block, and redstone signals don't pass through it, so it wouldn’t work the same with glass as with dirt.