Thanks for reporting!
The problem could be that in this case sudo isn't needed run openssl.
What you could do is manually edit the MakeCert.sh file (in FlexHub root folder), and remove the sudo from the openssl line. Then make sure the file MakeCert.sh can't be modified but can be executed.
Then run !createcert -force
The writing to MakeCert.sh should fail silently, and will then execute the manually modified file.