Have you looked into these reports at all ?
I research every report I receive.
I don't receive nearly as many reports as you might think.
Most folks just want help getting back to work -- and mostly that means I don't quite get enough info to find/fix a bug. I call them "drive by reports".
What I do know:
There are 9 known bugs in SiteMap as of today. You can see them here and follow along on my progress if you like. I'm pretty public with these sorts of things.
None of these bugs seems specific to Blog pages though.
There ARE two that are specific to RapidBlog + SiteMap ... so... kinda-sorta blog-ish???
But I don't think that's what you were talking about, right?
I do have one specific file that I have not completely diagnosed.
It seems to be related to SiteMap + Stacks and RapidWeaver 7.2 -- I don't think it has a blog involved there either, but it does have a very similar symptom: it hangs.
However it hangs on opening the file -- no preview necessary.
So... the long answer to your specific question: I have not done any research into SiteMap + Blogs. If there are errors there, they're news to me. And it would certainly help to have a file that demonstrates the issue.
One more thing: This is my integration-test file for Blog + SiteMap. My tests show that this file can open, save and export. And produces expected output.
We do lots of other testing, of course, but this basic test just shows that there's no fundamental flaw here. But both Blogs and SiteMaps have dozens of options. If I had to guess, I'd say the bug is hiding in some combination of those. Having a file that showed how specifically you're using SiteMap and Blog pages would help narrow down the search.