Aye. It's simply a warning message for something that's always been in there.
As part of the differences between thermal and kinetic weapons, it's always been stated that thermal weapons generate more heat but also dump small amounts of heat in the target ship. Though the announcement was never there, but the brilliant decision to add the warning with 2.1 dropping meant there has indeed been much confusion.
But not nearly as much as "impulse attack". I believe people have genuinely spent time looking up "impulse" effects, but it would appear to simply be a notification for any attack that physically moves your ship. Rails slightly knock your ship on hit, which generates the warning message, and a hysterical level of forum posts complaining their ship was just instaganked by a highly modded ship that made it "far more dangerous than their unmodded ship" -_-