A few things may give you clues:
systemctl status ntpd
That should tell you anything about the service that is current, including
when it last ran.
systemctl is-active ntpd
Indicates whether or not the service is currently active.
Look through the output looking for your service. The idea with this
command is to show what caused the startup to take as long as it did (so
you can optimize that), but as a result it shows all of the starting
services, in order, which may be useful.
Along with all of that it may be useful to know how you are testing
whether or not the service is running, just in case your test is invalid.
Finally, "Yast’ doesn’t have an NTP client or service of its own; it
configures the system one. I only mention this in case you feel Yast is
somehow doing something other than setting things up, or if you believe
its tool is a separate one; it’s not.
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