Jake Paul is under investigation ... this time by officials in Puerto Rico for riding a motorized vehicle on a protected beach.
To use a bullfighting metaphor ... Jake waived the proverbial red flag in front of a bull by posting a video of him and some friends tooling around a beach in golf carts, smack in the middle of turtle-nesting season. That's illegal.
It looks like the driver is his brother Logan, although we haven't been able to confirm.
Jake deleted the vid, but it's too late, because the investigation has been launched by the country's Dept.