They tested at a very low dosage and if that had adverse effects my guess is the only thing they could do was not publish it and do further research to determine the length of the adverse effects. I don’t know what Mars Petcare primarily makes but I doubt they’d pull any CBD products off the shelves if they did find adverse effects. Whether or not they would be liable for making statements contrary to their own research is a grey area. In my experience at least very rarely will a private business pay for research and publish if it runs counter to their objective but it has happened usually due to them realizing any other researcher would inevitably come to the same conclusion.

That’s just my take*