I submitted a bug report at KDE-Bugtracker.

SUMMARY
Seems to be a location and time based bug

STEPS TO REPRODUCE
1. Preferences -> Satellites -> Show Satellites -> Show only visible satellites -> OK
2. Choose a location, e.g. Frankfurt, Germany
3. Pause clock
4. Set time step to 1 hour
5. Advance steps in hour.

OBSERVED RESULT
If there where satellites drawn, they will disappear at some point.
After a few steps more they come back.

EXPECTED RESULT
Satellites shouldn't disappear-

SOFTWARE/OS VERSIONS
macOS: 11.2.3

ADDITIONAL INFORMATION
Also tested in Windows via Crossover

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