would love to know. because they really don't tend to do that, unless they are in the process of crashing into the thicker athmosphere. And that was not the case, as it's sharing a close enough orbit to the iss
Considering all the ways they've been ridiculously incompetent in their invasion of Ukraine, I could actually see this incident being due to ineptitude.
Not because of Kessler syndrome, just your run of the mill space debris reentering the atmosphere and increasing the amounts of certain metals up there that contribute to ozone depletion. In other words, that may well happen even if we're lucky and avoid Kessler syndrome.