Pyrex cookware can break in the microwave. So can glass cookware from other brands.

These incidents are RARE.

Your original claim is that they are "likely." This is wrong. Your new claim is that it "breaks in the microwave". Leaving out a qualifier implies it is inevitable and common. That interpretation is clearly wrong given the hundreds of millions if not billions of such glassware in use.

"Pyrex" is a brand name. You need to be specific. Do you mean Pyrex soda lime glass, Pyrex borosilicate glass, or both?

Why do you not care about non-Pyrex brand glassware?

> The platen glass is doped with a microwave absorbance metal to provide some protection to the magnetron

I am not able to verify this claim. As best I can tell, I was wrong - borosilicate glass is most often used, not lime soda. See https://patents.google.com/patent/JP2013063861A/en ("As the glass used for the turntable, borosilicate glass having a low thermal expansion coefficient and excellent thermal shock resistance is used.")

While boron is a metalloid (not a metal), it is not chosen for microwave absorbance reasons.

I do not believe your claim is true because "microwave absorbance metal" means the glass will heat up faster than otherwise, which is not what you want.