Timestamps in Home Assistant show different values

I’m having an issue with the timestamps in my Home Assistant installation.

When I view a sensor as entity in Lovelace, such as
it shows me a timestamp of 1 second ago.
However, when I click the sensor (in Lovelace), it shows 30s ago

as_timestamp(now()) - as_timestamp(states('sensor.pc_win_lastactive'))
template to calculate the time difference, it again shows me a timestamp of 30 seconds ago.

I believe the issue may be related to the time settings on my Home Assistant server.
How can I ensure that the timestamps are accurate and consistent?

Windows time is synchronized.
(The PC publishing the last active timestamp is also the one displaying the Lovelace)

Any help or suggestions would be greatly appreciated. Thank you!

I need help.