Trying to update the nodeagent service following the guideline found at IBM Knowledge Center failed, complaining about the value of the -username was not known.
Unrecognized parameters encountered on the command line: 'wasadmin '
It turned out that I had a slash at the end of the folder name for the washome, which then acted as an escape char for the double qoute
-washome "D:\WebSphere\AppServer\"
Changed to
-washome "D:\WebSphere\AppServer"
and all was fine.