I've had a small nibble on 1 strap once, and I've had a lifeline at the bottom chewed through, but nothing that would ever make me think that your case was anything other than a person.
I've owned and been hunting from Lone Wolf stands for 20 years now and have never had a single trap chewed on to that extent by an animal. Some of them have been left out for multiple years at a time. I'm 100% convinced it was a person.
I’m not sure I feel safe using a lock-on with these Missouri squirrels. They are a different breed. Maybe they got a hold of some of the local meth.