Mass Update Changes Unrelated Settings

When using the mass update form "Update Virtual Servers" to update all servers, several other things were changed that should not have been.

I selected only one item on the form:
DNS domain enabled? -- set to Disable

All other items were set to "Don't Change".

On the following status page, most domains simply had two actions, as expected:

Deleting DNS zone ..
.. done

Saving server details ..
.. done

However, some domains had these additional actions:

Modifying administration user ..
.. done

Updating Webmin user ..
.. done

Updating owner limits ..
.. done

Afterwards, I noticed that these domains had their bandwidth limits reset to unlimited. Also, when reviewing the Webmin Actions Log, it appears that some password hashes were changed in miniserv.users and /etc/shadow, and some quotas were modified, as in:

Executed command
edquota -u xxxx

Most of these changes appear to be minor, but I will apparently have to reset the bandwidth limits manually back to their former values, and I'm not sure why or how the password hashes and quotas were modified.

Status: 
Closed (fixed)