win32clipboard writing to clipboard on Windows 11

Recently I acquired a new laptop running WIndows 11; my previous one uses WIndows 10.  I encountered a strange problem:
I am using the win32clipboard backage (part of pywin32), and when I use SetClipboardData() to write text which consists ***entirely of digits*** to the clipboard, I either get an error (not always the same error message) or a program crash.  The problem does not appear if I use SetClipboardText() instead.  The problem does not occur on my old machine (where I used the feature extensively).
Sample program:
from win32clipboard import *
OpenClipboard()
SetClipboardData(CF_UNICODETEXT, "A")
SetClipboardData(CF_UNICODETEXT, "A0")
SetClipboardData(CF_UNICODETEXT, "0A")
SetClipboardText("0", CF_UNICODETEXT)
print("OK so far")
SetClipboardData(CF_UNICODETEXT, "0")
CloseClipboard()
Sample output:
OK so far
Traceback (most recent call last):
   File "C:\TEST*.PY", line 8, in <module>
     SetClipboardData(CF_UNICODETEXT, "0")
pywintypes.error: (0, 'SetClipboardData', 'No error message is available')
Can anyone shed light on this?
Best wishes
Rob Cliffe