The service uses a mixture of "Google Reviewers" and trusted users to moderate Map Maker contributions, but clearly the setup has some flaws. As such, Google has already suspended auto-approval and user moderation, instead relying on manual checks from its in-house team. The company says it's quickly accrued a huge backlog of user-contributed edits, so while it develops a new moderation system, it's suspending public submissions entirely. It'll come into effect from May 12th and while Google says it's "a temporary situation," it's also admitted that it'll take more than a few days to fix.