I wrote my observations about this in another topic: Observations about spam signups
In summary, I think those new fake members are tip of the iceberg. My observation is, some bots are making signup requests for way more high number of email addresses, and some of those email owners -somehow- clicks the signup link and completes the signup flow.
Maybe you can try to send a direct email to some of them (from countries you can talk in their language), and kindly ask how they decided to be a member.