codec can't decode byte 0xff in position 0: invalid start byte

Hi awsome developers!

I'm running a Proxmox (6.04) cluster on three Intel NUCs.
These are the models in use:
  - NUC8i7BEH
  - NUC5i7RYB
  - NUC5i5RYB

I decided to try out the Landscape on prem. Landscape is installed in a VM running Ubuntu 18.04.

As for clients, I used my dns servers, which are LXC containers. 2/3 servers worked great and they checked in to landscape. However, for some reason one of them didn't.

The error I get is:
Failure: landscape.lib.amp.MethodCallError: timeout

very similar to what is reported in this report: https://bugs.launchpad.net/landscape-client/+bug/1459641

However, what happens when I run landscape-client --config=/etc/landscape/client.conf differs

2020-01-16 23:54:06,031 ERROR [MainThread] Error running event handler landscape.client.broker.registration.RegistrationHandler._handle_pre_exchange() for event type 'pre-exchange' with args () {}.
Traceback (most recent call last):
  File "/usr/lib/python3/dist-packages/landscape/lib/reactor.py", line 90, in fire
    results.append(handler(*args, **kwargs))
  File "/usr/lib/python3/dist-packages/landscape/client/broker/registration.py", line 192, in _handle_pre_exchange
    "vm-info": get_vm_info()}
  File "/usr/lib/python3/dist-packages/landscape/lib/vm_info.py", line 29, in get_vm_info
    vendor = _get_vm_by_vendor(dmi_vendor_path)
  File "/usr/lib/python3/dist-packages/landscape/lib/vm_info.py", line 62, in _get_vm_by_vendor
    vendor = read_text_file(sys_vendor_path).lower()
  File "/usr/lib/python3/dist-packages/landscape/lib/fs.py", line 73, in read_text_file
    content = read_binary_file(path).decode("utf-8")
UnicodeDecodeError: 'utf-8' codec can't decode byte 0xff in position 0: invalid start byte
2020-01-16 23:54:06,032 INFO [MainThread] Starting urgent message exchange with https://landscape.aberg.io/message-system.

I've attached the full output of this command.

Client info:
----
# apt-cache policy landscape-client
landscape-client:
  Installed: 18.03~1075~git.256ad02~ubuntu18.04.1

# lsb_release -rd
Description: Ubuntu 18.04.3 LTS
Release: 18.04

# cat /sys/class/dmi/id/board_vendor
Intel Corporation

# cat # cat /sys/class/dmi/id/bios_vendor
Intel Corporation

# cat /sys/class/dmi/id/chassis_vendor
���������������������������������

# cat /sys/class/dmi/id/sys_vendor
���������������������������������

All three containers are running Ubuntu 18.04.3 LTS.
I've tried to see if it would help to migrate to one of the other NUCs, sadly it didn't.

The cerificate is the same on all containers with the same permissions.

Regards