When we deploy a vm for the first time the generated password is applied.
When we change the password and reboot, the changed password gets reset to the initially generated password or a newly generated on.
On the router vm the password file in /var/cache/cloud looks like this:
10.1.1.199=coth6harf2oG and stays that way even after the fetch.
On Cloudstack 4.4 the file gets updated like this once the password was fetched: