Get Pre Login Banner always failing with FAIL : AttributeError: 'NoneType' object has no attribute 'decode'

Using Get Pre Login Banner with or without host name, always returns:
FAIL : AttributeError: 'NoneType' object has no attribute 'decode'

I don't know if this is because I am using a jump server to reach the server under test.

Robot Framework: 6.1.1
Python: 3.10.6
Host OS with Robot Framework : Debian bullseye/sid
Jump OS: CentOS Linux release 7.9.2009 (Core)
OS under test: Debian 9.13
SSHLibrary: 3.8.0

DEBUG loglevel:

20231128 11:05:35.495 :  FAIL : AttributeError: 'NoneType' object has no attribute 'decode'
20231128 11:05:35.495 : DEBUG : 
Traceback (most recent call last):
  File "/home/ibas/.local/lib/python3.10/site-packages/SSHLibrary/library.py", line 1125, in get_pre_login_banner
    return banner.decode(self.DEFAULT_ENCODING)
AttributeError: 'NoneType' object has no attribute 'decode'

Start in SSHLibrary/library.py at get_pre_login_banner around line 1125, then reproduce the keyword with and without a host name using the listed environment details. Compare the banner value returned in each case; done means the keyword no longer raises the reported NoneType.decode error and its behavior for an absent banner is verified.