Sounds a lot like some mass activity that Kinetic didn't like happened after 1st of July so they just took the whole forums off-line to hide it, and have now restored it prior to the times of trouble.
Well you're half right.
The "mass activity" was Kinetic itself deleting thousands of old, but still potentially useful, posts.
It was the user community that didn't like it, and said so in no uncertain terms, so Kinetic took the forum offline while they reviewed their actions.
Hopefully any future pruning of posts and threads will be done more judiciously.