I'm not sure how many people were really in danger of their save files being corrupted by last week's Quiet bug. After all, it would have meant taking someone other than D-Dog on a mission. As if.
Those who did, for whatever reason, bring Quiet along on missions 29 or 42 risked having their progress erased. In a game based around logical outcomes to systemic actions, that's not a particularly logical outcome. Luckily it's now fixed—at least on PC and PS4—thanks to an update announced by Konami.
The "Quiet bug" in #MGSVTPP has been fixed for PS4 and PC. The remaining platforms will follow soon! Stay tuned! pic.twitter.com/lidhRnxIFf September 14, 2015
Other platforms still aren't safe from Quiet's wrath, but should be pretty soon.
Personally, I was never in any danger of falling victim to the bug, having only reached mission 7 after 16 hours played. Others have done more, and got further. You can read their tales of humorous heroism here.