In addition, by blocking someone who was previously a friend, you automatically unfriend them. At least unless you say otherwise.
But during May 29-June 5, affected users had their block list changed.
Rescue of boys from Thai cave delayed by floods, forecast
If it continues to rain for four months, there's a strong possibility that they might not be able to dive them out. But heavy monsoon rains are forecast for Sunday. "If there are risks, then we will not be extracting them".
Do you block anyone on Facebook?
Separately, Facebook announced several API changes on Monday, which are meant to better safeguard user data.
Apparently, the bug did not cause unblocked users to become friend with the users who had blocked them even if they were friends before getting blocked. Also worth noting, is the fact that the bug would only let these users see what you shared publicly, not what you shared with your friends only.
Facebook's audience selector tool usually remembers the audience you shared with the last time you posted something (public, friends, friends except., or only me) and suggests the same audience when you share again.
Facebook has not said how many unblocked people took advantage of the bug to make unwelcome contact with the people who had blocked them. While Facebook found a solution for the problem, it doesn't raise confidence in the company's ability to keep its user data safe. The incident adds to the list of several other similar cases when the social media company has (un) intentionally revealed user data and details, which should have otherwise remain inaccessible.