Hurrah! Finally, a (partial) resolution to a problem that's been around for over 20 years... Yes, a full error set would be nice, but I suspect that that would involve a serious overhaul of the error handling system. But this is a good step forward. Thanks, Steve, for bringing it to our attention.
...but did you say it's TF-dependent? Why? Why can't they just surface this extra information by default? Is it because they're putting it out as a different error message ID?