Nobody is claiming that this changes are more than astronomically possible to be produced by random processes, the title in such case should have read "... raises robustness concerns" instead of security concerns.

In every security system, it is assumed that if there is an attack surface, sooner or later an intelligent adversary will come and exploit it. And there is a long precedent saying that if you see the word "linear" anywhere in the attack surface description, the adversary is bond to come sooner rather than later.