copper is a soft and very expensive metal so soft that it will try and curl under heat. if it is a thick piece of copper then the guy that put it in spent way more money than a piece of ceramic glass of what the guy did that owned my h2 before me was put in two sheets of glass. and that is what could be that it is eating wood and you are not getting much time out of a load
Thank you for clarifying. The gentleman that retrofitted that piece is a roofer—specifically a copper roof restorer of preservation listed buildings, he stuck in what he had to keep warm on the job site I believe, (as he tells it). It just so happened to be a piece of excess copper from a job, alebit that was a little while ago, though he’s not one to begrudge a man in need the price of copper .
I was worried it might somehow be toxic, but glad to read yours words of caution. Thank you!