white circles come from ship

what is this? I saw white circles coming from an enemy ship and we don't know why they started appearing when i mentioned it later. what did he do to make it happen?
white rings, I'm told it was sensor, but only in older versions. ..

My help says to use A or K for turbo. Do I have a broken version?

EDIT
Got it

When you're active cloaked you see white rings come out of people who have sensor on