But this is probably not related to espionage. As noted in the CNN article, it’s very common to have cell connections embedded in industrial hardware these days.
The wsj article addressed that and said there’s a protocol for approving devices. These were found in devices that were not approved and where the users didn’t know there was connectivity.
Sometimes these kinds of stories are knee-jerk “China bad” stories. And sometimes they are much worse than reported, but downplayed to avoid embarrassment and panic. Hard to know which.