Confirmed for 1.10, glowstone not affected. You can see the result with cobweb on this video : https://youtu.be/fZa-kKz-K3E
What i think is that when the ceiling is sealed, all the air blocks's light level underneath are updated but they omit other blocks (for optimisation purpose) so cobweb is not updated except if you place the block just above it (for glass and other stuff it works though)
F3 confirms that the light is skylight, not block light
Brasseur Dylan
Confirmed for 1.10, glowstone not affected. You can see the result with cobweb on this video : https://youtu.be/fZa-kKz-K3E
What i think is that when the ceiling is sealed, all the air blocks's light level underneath are updated but they omit other blocks (for optimisation purpose) so cobweb is not updated except if you place the block just above it (for glass and other stuff it works though)
F3 confirms that the light is skylight, not block light