On warranty return it’s tough for manufacturers to take them back, because they’d have to pay for the shipping and lithium batteries are DG, so they’re required to be properly packaged with the correct DG markings. They’d also eat a hazmat surcharge for every shipping label they send out for rma.
It’s cheapest for companies to just let you keep the faulty one and figure out where to recycle it. Not saying that’s right or wrong, but reality of shipping batteries these days.
It’s also not legal in the US to ship a lithium battery by air that is known to be faulty. The more you know