You probably have multiple decoders running but only one of them will work (unless the 2nd decoder is running with different ports and not trying to use the SDR but rather getting the data via TCP).
You can use pgrep to see which processes are running.
Typically checking for dump1090 / readsb is sufficient.
pgrep -af dump1090
pgrep -af readsb
My install scripts usually correct those sort of issues by making sure only the decoder you’re installing is installed, they remove the others as this is a somewhat common issue.
Automatic installation for readsb · wiedehopf/adsb-scripts Wiki · GitHub
Automatic installation for dump1090 fa · wiedehopf/adsb-scripts Wiki · GitHub
Skyview belongs to dump1090-fa so that will only work if you use dump1090-fa as a decoder.
But piaware will work just fine without dump1090-fa as long as any decoder is providing beast data on 30005.