In my case, the Node.js upgrade from 9.4 to 20.5 placed the Node.js 20.5 executable to the /usr/bin folder, but the previous version still existed at the use/bin/local folder.
find /usr -name "node" -print 2>/dev/null
So I deleted the previous version:
rm -f /usr/local/bin/node
Then I restarted the shell.