Do you have them listed as safe/added to contacts/not spam? I often find that when it comes to under the radar type stuff not just Bitcoin that it's just the anti-spam kicking in because the software thinks that the emails are coming in from an unusual source and of course, those messages you're showing are automated, so that will most likely be setting it off as well.
That's an ok solution for me (I prefer to think that Gmail will learn, now that I've unmarked all of these as spam.
How about the next poor sap?
The real question is why they were tagged spam to begin with. I had received many bitcointalk emails before these, which passed quite fine.
Are there any industry best practices bitcointalk isn't following?