This is a somewhat misleading title. The car was intentionally set to cruise control by the owner, but the cruise control could not be turned off until Mercedes remotely found a way to disable it about 100km later.
Personally that's exactly what I got from the title; it says it was stuck in cruise control. To me that indicates cruise control had been enabled, and then became stuck on.
I believe I was misled by "remotely controlled vehicle stuck in cruise control," which (to me) implies that the remote control feature was somehow relevant to not being able to disable the cruise control. The article did not talk about remote control until it mentioned using it to disable the cruise control.