@kagbasi-wgsdac Normally, this issue has already been fixed upstream since a long time.
XS tools 9.4.0 is pretty old, you should update to 9.6.0 which should contain a newer Xenbus balloon driver.
Better yet, you can switch to the XCP-ng tools (as you've done), since the XCP-ng tools are what we now recommend for all Windows guests.
A new version of the XCP-ng tools is coming out soon with lots of improvements.
You can check for the driver version by running this command on the host:
xe vm-param-get uuid=<VM UUID> param-name=PV-drivers-version
For XS 9.6.0, I'd expect it to report xenbus: XenServer 9.1.13.23.