I know that the physical retail Microsoft Stores in the US have been replacing these at no charge (even out of warranty) if the battery is swollen. f you are in the US, you should go to the closest physical retail Microsoft Store https://www.microsoft.com/en-us/store/locations... - outside the US, contact Business support (you mention having 15 so I am assuming this is a business environment).
I don't work for Microsoft, and I can't really say anything about why this is happening, but I agree, it is a real shame. I've seen a few of complaints like this recently, but at least all the folks I sent to the stores were able to get replacements at no charge. (Plus the added headache of having to reinstall software, etc. etc.)
Sorry you are having this issue on multiple devices. I hope my response is helpful. If it was of assistance, please DO mark as Answer.