Someone or organization is mass hacking Hikvision devices, actively and systematically running a script / program across the Internet that looks for Hikvision devices, finds them, and, at least, locks the user out.
The most significant misconception is that someone is simply randomly or manually looking up individual devices and changing admin passwords. This is absolutely not the case as Hikvision themselves have acknowledged.
This is a serious problem for Hikvision and their customers.
This is also the case of someone who is unethically and probably illegally running these hacks.