At smp7 I've seen many straight lines of light under the ocean If you seen these you should know there is a mineshaft directly below them, could be near the surface of the ocean or could be at bedrock. This glitch is very similar to x-ray, please fix it if you are able to.
There are lots of light glitches like this since 1.2, causing a block update or disconnecting and reconnecting should fix the problem.
