My dog keeps shredding our outdoor lounge cushions

This is the second lounge we’ve gotten, the cushions are just foam with covers on them, the covers were a thick fabric but she’s still managed to chew through it.

She 9 months old, a husky x border collie x Nova Scotia duck rolling retriever and Labrador.

I’ve tried putting things on the lounge to stop her, I’ve sprayed it with vinegar, I’ve used fitted sheets over the whole lounge but none has worked.

She only does it when she and our other dog are locked outside, and no one is in sight. They get locked outside when my partner gets up for work because if they’re left inside they get zoomies in the morning and end up waking the baby up early.

so whenever she’s locked outside and can’t see anyone through the window, I’ve never actually seen her do it, but I am 100% confident that it’s her and not our other dog-he’s 4 and has never been a chewer, and she is still a puppy.