Could it be that the reporting feature itself isn't working in v. 3? I had another kind of crash that is pretty common for me (this one comes when I add/move folders, or something), and again, error reporting is greyed out!
The reporting feature isn't broken. A crash of Zotero—the restart message in the center pane—often doesn't generate an error, because it has a different cause. A sync error will almost always produce an error report.
Thanks