But every time I have used 'apt update', for as long as I can remember, it has always reported 'fetched 13 MB".It is using the previously downloaded repo data because it hadn't changed.That "Fetched 15.0 kB" seems rather low, has historically been around 13 MB.
But I will accept you are right because swapping back to what it was originally, as per OP, now delivers as expected -
So I guess 'non-issue'.pi@Pi3B:~ $ sudo apt update
Get:1 http://raspbian.raspberrypi.org/raspbian buster InRelease [15.0 kB]
Hit:2 http://archive.raspberrypi.org/debian buster InRelease
Get:3 http://raspbian.raspberrypi.org/raspbian buster/main armhf Packages [13.0 MB]
Ign:4 https://download.puffinbrowser.com/repo stable InRelease
Hit:5 https://download.puffinbrowser.com/repo stable Release
Get:6 http://raspbian.raspberrypi.org/raspbian buster/contrib armhf Packages [58.8 kB]
Get:8 http://raspbian.raspberrypi.org/raspbian buster/non-free armhf Packages [110 kB]
Get:9 http://raspbian.raspberrypi.org/raspbian buster/rpi armhf Packages [1,360 B]
Fetched 13.2 MB in 9s (1,404 kB/s)
Reading package lists... Done
Building dependency tree
Reading state information... Done
All packages are up to date.
Statistics: Posted by hippy — Tue Feb 06, 2024 12:16 pm