You're definitely not losing it. That site has a proper history of shadow activity and I'd wager there's more going on there than most people realise.
I did a solo EVP session near the old mill pond back in 2019 and picked up some genuinely odd responses on my Zoom H5 - nothing I could fully explain away. Didn't see a shadow figure that night but I had this strong sense of something moving at the periphery of my vision, that classic "just out of sight" thing that you can't quite pin down.
What did yours look like? Tall, humanoid? Did it move in a straight line or more erratic? The reason I ask is that the behaviour can tell you a lot about what you might be dealing with - residual impression versus something with actual intelligence behind it are two very different things in my experience.
Would love to get a small group together out there if anyones up for it. I've been wanting to go back for ages.