Power Isolation generating error in KiCAD
I believe you get the error at all the power in pins of your circuit: you are not providing them a power out connection since your power line is in series with the ferrite bead, which is passive/passive.

If you want to keep your filter symmetric, and it is symmetric, you can use the power flag. The power flag is basically a fake power output pin, where fake means it has no real counterpart. You place it on nets you know are powered to tell the DRC all is fine.

You can find the power flag component in the 'place power port' menu.