Why are these pistons (indirectly) powered? But the others completely not? None of them update with a block (Not really a BUD piston I believe, or is it?)
Relevant quote from the wiki (emphasis mine)
In addition to the normal methods of activation described above, pistons can also be activated if one of the methods above would activate a mechanism component in the block above the piston, even if there is no mechanism component there (even if the block above the component is air or a transparent block).
And some relevant images from the same page