Whenever I upload a video to YouTube all other browser tabs behave like there is no connection at all. It even affects my phone and other computers on the network therefor I think it has to do with my router. When the upload is done everything works normally again. I never observed this behavior with any other upload.

My router is a Fritz!Box 7390 and my uploading PC is connected through a 1000mb/s switch (wired) to the router.

Uploading through another browser does not change anything.

I understand that other sites become slow as the network resources are limited, but stopping altogether feels wrong.

speed.io measures for my internet connection: 40.894 Kbit/s down, 2.685 Kbit/s up, 29 ms ping, 2.048 con/m connects