As I mentioned before, I contacted Profile Design about this, and they concluded that it failed due to corrosion (as my mechanic initially said lol). This is what they said:

"That first picture is very helpful. What looks like happened is there was some scratch or chip in the carbon which exposed the aluminum. Once exposed the sweat and/or drink mix started doing work on it. I would like to get that stem back for further inspection. "

I'm guessing this is because the AL beneath the carbon layer is not as protected as the normal anodized AL stems. So once the carbon starts to peel off, sweat and hydration start the corrosion of the AL, and you won't be able to notice this because of the carbon layer that is hiding the corrosion of the entire stem.


They also told me that the stem was discontinued, and they offered to replace my stem with a new top of line stem plus a new handlebar and aerobars, which is great. They responded promptly and seems they have very good customer service by the way.

However I am concerned about what happened since many people could be riding this same stem without knowing that it may have a design problem and after all, this stem is still available in many online retailers.

To make things worse, I went riding yesterday with my group, and a fellow cyclist had the same stem that I had, and it was already showing the same signs of peeling that mine had. After hearing my story, he was going to change the stem ASAP, but this means that there may be a lot of people using this same stem, not worrying about the peeling since they would never think of the catastrophic failure that could happen. I am attaching photos of his stem, so that you can see what the initial peeling looks like. This was exactly what happened to mine, before it suddenly broke in half.

I have contacted Profile Design again about this, and sent them these photos too, since I think they need to issue a warning or recall before a tragic accident occurs.