Webmin / Usermin do not start at boot time

For an unknown reason, webmin and usermin don’t start anymore at boot time.
They correctly start afterward by issuing /etc/init.d/webmin start /etc/init.d/usermin start without any error.

In System > Bootup and shutdown, they are both set “No” in the “At boot?” column
when setting to “Yes”, they keep the “No”

No errors in log files /var/usermin/miniserv.error and /var/webmin/miniserv.error

Thanks in advance for help