but they shared symbols for the tishell64 DLL to help us understand what was going on.

This is perhaps the most surprising sentence in this article. A proprietary software company sharing debugging symbols (which are basically the closest thing to source code that isn't source code) when you just ask their support about an issue is something that I'd never expect to happen.

I was surprised also when this happened, but pleased. The trust was nice. The fact that they needed to give me the symbols in order to understand the issue was surprising. Why couldn't they find the calls in their source? Or analyze the trace themselves? Curious.

Symbols for Windows system DLLs has been available for ages, downloadable in one click directly from within Visual Studio. So it's not without a precendent.