Weird speed issue when downloading via browser

[sanji]

Hello,

this is my first post here, as I'm having weird speed issues.

I'm using OpnSense 20.7.3 at home as my Router/Firewall. It is connected to my Cisco EPC3212 cable modem. OpnSense is running as a VM on Proxmox.

It worked great, but today I noticed that I'm getting slow download speeds when downloading files in my browser.  (200 - 900 KB/s). Usually I get my full bandwidth of 50 MBit/s.

I tested to download the same files simultaneously on other networks (at work, on mobile data) and the speed was good. It's just slow on my network at home.

I'm having this problem on different browsers, different computers, via cable and wifi, and even on my mobile phone connected to wifi.

BUT:
I just downloaded games via Battle.net and Steam and there were no problems. I could download with speeds of about 6,2 MB/s.

Speedtests like https://speed.cloudflare.com/ and https://speedtest.net/ also show good results.

So it just seems to happen when I'm really downloading a file via browser.

What could cause such an issue?

Thank you very much for helping me!

EDIT: Streaming Netflix and Youtube Videos is also fine.
But downloading one of these test files (https://speed.hetzner.de/) is slow. I just get about 1 - 1,5 MB/s now. But downloading at the same time on mobile phone or from my computer at work is very fast.

I never had something like intrusion detection or web filtering enabled...

EDIT2: I just noticed, that video files (.mkv and .mp4) from google drive download with full speed, but .zip and .bin files are slow for example.
This sounds like some web filtering is done, but i dont have and never had anything like that enabled.

[Rickman]

I have the same issue, did you ever figure out what was causing it?