[SOLVED] Confused about low transfer speeds

[zero.]

I need help understanding what is happening with my home setup.
Environment:
In my lab, I have Proxmox running:

• Opnsense VM with PCI NIC passthrough and one Linux bridge (vmbr0) to feed the VM and CT
• Debian VM with vmbr0

besides, I have 2 other physical PC: office PC and movies PC.

The problem:
If I copy a file directly from Debian VM/movies PC to my Office PC I get 110MB/s which is normal.
If I copy a file directly from Debian VM to movies PC I get the same speed as above.
The other way round, I got the same speeds.
The problem is when, from my Office physical PC I open VM share and try to copy a file to movies PC share, the speed only 50MB/s.
Is it normal?

Screenshots:
PVE network tab:

Opnsense hardware

Debian VM:


Any help would be appreciated.
Thanks in advice.

 

[zero.]

It turned out that the Ethernet cable of the office PC was in bad condition