It happened when Tahaan bombarded the bit with energy. For the few seconds before it blew, it was more negative than positive, like Tahaan itself. So, when it blew, that energy tainted the bits around it, including the larger chunks, converting some of the positive into negative. Or, at least, that's my idea. I was thinking it could server as a consequence, the first of many I'm sure, for the beings when it comes to tampering without thinking, like Tahaan does, all the time :P If you really don't like it, then I could take it out. Through it's bombardment it made something that was not balanced.