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Four vehicles have been left with their windows smashed after heading through the same stretch of motorway.
Kent's Roads Policing Unit (RPU) has tweeted to warn drivers of the incidents which have happened just after junction 2 for Wrotham.
Officers said the rear or the passenger windows were broken.
In a reply on Twitter the RPU said it does not know exactly what has caused the damage.
But one driver has raised fears the latest incidents could be 'someone taking pot shots' and he believes he experienced something similar in June.
Lee Hiatt replied, sharing his tweet from June 26, sent to the unit, suggesting patrols were sent to junction 2, adding: "Think someone is taking pot shots with a pellet gun.
"Another car and lorry pulled over behind me.
"It was not a stone as the road was clear in front of me."
He said he did not get a reply.
The RPU is asking anyone with information to call 101 quoting reference KP-20200801-1504.