The common interpretation is that Ms-PL is intentional designed to work like BSD, but to forbid code to be put under other free and open source licenses.
Ms-PL allows you to distribute derived works freely under any license but only if it is in binary form. If you distribute code in source form, then the license change style and requires that all code to be under the Ms-PL, and only under the Ms-PL. Since practically all free and open source project distribute code in source format, this makes code under Ms-PL incompatible with most projects.
Isn't it incompatible if, and only if, you modify the original? For example, I can make an open source program that uses OpenSubDiv and distribute that open source but I cannot modify OpenSubDiv and distribute the source?
Reading the license text, I do not see any exception for distribution of exact copies. What the license text say's is: if you distribute any portion of the software in source code form, you may do so only under Ms-PL.
Project will use the technology described in the now open patents, but the source code will likely never see any use beyond as a reference manual.
Ms-PL allows you to distribute derived works freely under any license but only if it is in binary form. If you distribute code in source form, then the license change style and requires that all code to be under the Ms-PL, and only under the Ms-PL. Since practically all free and open source project distribute code in source format, this makes code under Ms-PL incompatible with most projects.