If you are not aware, you may want to look at https://www.saferproducts.gov/PublicSearch/Result and search for Surface Book. There were 1800+ reports filed, and I am about to add 1 more.
I have had my Surface Book for 3-4 years. A few weeks ago I noticed yellowing around the screen edges, but figured I must have been working it too hard. A few days later, I noticed the lid not close all the way. After examining it I noticed the bulge. I submitted a support request right away, and then started doing some searching while I waited. That is when I found this article:
https://www.engineering.com/story/the-microsoft-surface-swollen-battery-problem
The support I received has not only been the most abysmal, it boarded on fraudulent. When I first contacted support I was given the same blasé disregard for the seriousness of the issue or the danger posed to my family, some "bad science" infused rationale how I shouldn't power it on but that it did not pose a danger, then some patronizing platitudes, an attempt to transfer me to purchase a new product, followed by an empty promise to escalate to an "extended support team" and then a week of silence. Shortly after I requested a follow up, I separately received a notification from my credit card company that a large purchase was made at the Microsoft online store. Since I had not approved or authorized any purchase, I immediately logged in, cancelled it, and found that an 'Out of Warranty battery' was ordered in my name, with my account where that credit card is set to default, but to be shipped to a different address.
I tried reaching out to Microsoft but it's nearly impossible to talk to a person. The support person interacted with called the order a mistake and refused to escalate my case 4 times since this incident.
Most ironically, I was seriously considering replacing the laptop after the end of the year anyway, even considering the Surface Laptop Studio, but this situation has most definitely given me pause.