Surface Pro 4 Bulging Battery / Screen. 3 1/2 years old.

Yep. I am the same. Went and reported it (mine was a surface laptop from 2017). I was offered an 'amazing' deal whereby I could part with $1000 AU to get a replacement model (exactly the same).

So really, I could get a model that is over 3 years old, susceptible to the same issue, but pay $1000. I'd effectively be spending a collective $3k AU on a machine that is potentially unsafe. 

Or I could use that money to go toward, I don't know, maybe anything that's not a Microsoft product?

That's what I said to support and I received no reply. 

I'm lodging this with the ACCC seeing if this can be covered under the consumer protection law for implied warranty and will see how I go!

Same with me, I'm done with Microsoft. Have bought a DEL XPS13. Its great and cost $1600 for high end model with latest 11th gen i7 processor. Much better deal than an old out of date Surface for $600!

Back in December of 2015, I ordered two of the Surface Pro 4's, one for me and one for my wife. In October of 2019 I noticed that my screen was pulling away from the frame of my Pro 4. I knew that both Surfaces were out of warranty, but I called Microsoft support about the problem and was told to make an appointment at the nearest Microsoft Store (they were still open at that time) to have it looked at.

When I took it to the store, they looked at it and told me it was a "bulging battery" and is very dangerous. They told me that there was an internal memo that was sent to the stores telling them that if customers come in with a Surface Pro with a bulging battery, to swap out the unit with a replacement unit. The manger told me that because they had replaced so many of the Surface Pro 4's due to this problem, they had to swap it with a 'refurbished' Surface Pro 5. Because the Surface Pro 7 had just been released a few weeks prior to my visit, I asked if I could do a trade-in of the Surface Pro 5 towards a Surface Pro 7, which they did. I ended up paying about $450 for the new Surface Pro 7.

Jump to today, a couple of weeks ago, I noticed that my wife's Surface Pro 4's battery is starting to bulge. I called Microsoft about the problem but this time they told me that because it was out of warranty, which I already knew, I would have to pay $450 to swap it out with a replacement unit, or upgrade to a Surface Pro 7 for $750. I told them that is a known problem with the Surface Pro 4 battery and how they replaced my Surface Pro 4 for free less than a year ago. They said that they're current policy for 'out of warranty' Surface Pro's is a $450 swap.  

I have an old Lenovo Twist that I've had since it came out and it is still going strong. The battery life isn't what it used to be, but it is still usable on battery for a good hour and a half. If that can last for this long without 'bulging battery' problems, so should the Surface Pro 4.

To solve the problem, I just pre-ordered a new ASUS ZenBook Flip 13 UX363EA-DH51T. Sorry but I won't give another penny to Microsoft for hardware that they apparently think is disposable.

It looks like Microsoft is not handling the issue correctly and consistently. 

Lack of consistency: I just spoke to a Microsoft Surface customer representative and got this "solution":  Per the rep: "Unfortunately your device is just out of warranty, so you need to pay $450 to get a refurb Surface Pro 4, with the exact same specifications." They refused to comment whether or not the refurb would have the same faulty battery (so no guarantee of the issue to reoccur or not) and they informed me that the warranty on the refurb would be only 90 days.  After specifically asking about other options, e.g. upgrading to a newer version, or providing a discount for a new latest spec Surface Pro, I was informed that those options are not offered. Based on some posts above, it seems that I've been misinformed, or that Microsoft has different "standards" for different customers? Also Microsoft does not seem to inform us consistently about any safety issues of continued use of the device. 

How Microsoft is handling this issue the wrong way: Like most of us, we NEVER had any swollen battery issues with ANY other tablet or laptop. The fact that so many of us have this issue points to design and / or manufacturing flaws. Microsoft is well aware of the magnitude of the issue: the issue is even a prepopulated field in the dropdown list of Surface problems.  Yet they claim that there is no wrongdoing on their end, and that "we already provided the solution to customers by extending the warranty from 1 to 3 years". Yet, most of us are experiencing the issues after the 3 year window. How convenient for Microsoft...  Also, with this they are essentially saying that their ~$2000 devices only have a life span of 3 years? But by not offering a replacement with a NEW device, or at least offering a significant discount on a new Surface Pro they are really offending customers, endangering them (fire hazard, leaking chemicals, etc.) and potentially causing further financial damage (lost income, for those of us that use their Surface for work, while waiting for a replacement). The only sensible solution would be a formal recall program.

Class action lawsuits have been filed for much less...

I have given up with Microsoft support. The CSR's have been helpful but no way are Microsoft going to budge from there position of $450 to replace like with like once the device is three years old despite being fully aware of the problem.

When one spends $1800 plus on a device I don't think its unreasonable to expect it to function safely for four years or more. This swollen battery issue, by Microsoft's own admission, means you should discontinue use of the device so if you are not prepared to accept their very bad deal the device is only fit for the trash can.

I would be happy to accept a trade in value equivalent to the $450 replacement cost to buy a newer machine but Microsoft don't listen to that, they just offer you a paltry $115 trade in and stick to their entrenched position so I have decided to move to Lenovo and will never buy another Microsoft device.

However, if anyone is considering class action against Microsoft I would jump at the chance to join he suit.