Hi! I was building a base that was going to utilise the green corundum lamp when I noticed that it doesn't emit light at all when placed. It emits the appropriate light level of 15 (default value in the config, this was not set to 0 by me) when I hold it in my hand, but when placed, the light level is 0. When I change the light value in the config, once again it only affects it when it's in my hand. I have also tried the other colours of the corundum lamps and they also act like this.

Hope you can get it fixed soon :)

Have you tried applying redstone power?