That’s what happens when producers of consumer items are not regulated. There’s no downside besides cost, so producers use the cheapest method available to get their product to market.
There’s a video on YT about a guy repairing a single use cock ring. A viewer apparently sent in his used cock ring for repair. Creator discovers it doesn’t work because of a corroded battery connection. I think he later finds the battery at a local store or orders it online. Replaced the battery and the sex toy is now functioning again.
He even adds some liquid resistance and warranties the item against further damage (or so he says, haha)