Well, whatever. I've been gv'ing a lot recently due to warping - game is as unplayable for the warper as for the warpee.
I've been spending a lot of time looking at the net status screen to see if there are any actions / situations which provoke it, but there's nothing which works consistently. I can be flying alone, with nothing but blue sky above and cloud below, and get huge sawtooths in the pattern. Or small ones. Above the line. Or sometimes below it.
Then, as randomly as they start, they stop again.
Not sure there's anything I can do at this point.