OnePlus is apparently still collecting some user and system data through a system app called OPBugReportLite. The app is enabled by default when you power on your smartphone and collects battery stats, kernel panics, your device's crashes and sends that compiled information to a server in Singapore every 6 hours. The app was discovered by a Twitter user Elliot Alderson. You can check if the app is present on your OnePlus device by going to Settings - Apps - Show system apps and searching for BugReportLite in the list. By default the app dumps mostly battery stats, which is fine...
Source: https://www.gsmarena.com/fool_me_twice_oneplus_has_a_system_app_that_sends_out_data_to_a_server_every_6_hours-news-28380.php