https://bugs.winehq.org/show_bug.cgi?id=57545
--- Comment #8 from Esme Povirk madewokherd@gmail.com --- As for the invalid method header format: what's most likely supposed to happen is that some method is supposed to decode that method in memory before the runtime reads it. Mono is probably doing something in the wrong order.
<Module>.cctor is called first and runs to completion. Afterwards, at least one method is called that dnSpy isn't able to display, indicating that it decoded successfully. That method never returns, though.
Some of what methods Mono is compiling and why may reveal something, but this kind of investigation is time-consuming, so I'm going to set it aside for now to triage other bugs in my queue.