Mystery Bluetooth MAC addresses

Mystery bluetooth MAC addresses. Recorded using the Samsung built-in screen recorder, Android 11. The first part of the clip was done using a downloaded app. The second part was using the built-in Bluetooth app.

The downloaded app is called
Bluetooth Finder & Scanner by Little Angel. The scan was made in a bus of about 10-15 people while over Harbour Bridge which is 2km. The app gives you 3 lines of info. First line is the device name. The second is the device type. The third is the MAC address.
Below the signal strength was my distance from the device.

Most of the devices had no name and no category. Let me know if you think you know what these unknown MAC addresses are.

MACs ought to have a vendor assigned to them. There are online MAC checkers which tell you which vendor they belong to.
You can pause the video and try entering them to an online checker. You only need to enter the first six characters ignoring the ":" and it's not case sensitive

Some devices generate random MACs but they give out at least a device name. Our Nikon DSLR doesn't have a fixed MAC. Using random MACs mean not paying licensing fees to IEEE, which save the vendor money.

In the built-in Bluetooth app, at the second part of the clip, you will see 2 devices that start with 13/VAL-TX. These belong to the bus and are on other buses as well. They are there whenever I do a scan.

If you're using Android 8, you will see the mystery MACs but you won't see their distance from you.

I've explained in detail my process and what I know. I've been scanning for some months and my scans give consistent results and I also use 5 other Bluetooth scanner apps. The apps detect devices up to 31m away so I could also be seeing devices from nearby cars.

I've been using Bluetooth for about 8 years and I don't remember seeing mystery MACs in the list. Any theories or ideas?