When placed or moved by a piston, target blocks do not update the directionality of redstone dust, despite updating its texture. However, redstone blocks do. This is most likely due to the fact that redstone dust will update its directionality when its power strength changes, resolving the buggy behavior with the target block.

The difference in behavior of the target and redstone blocks is unintuitive for players, even if it makes sense from a game code perspective.

Images in order of date:

Dust power direction failed to be updated by target block.

Dust power direction updated by redstone block.

Again, dust power direction failed to be updated by target block.

Dust power direction redirected by target block after signal strength of dust was changed.

Dust power direction failed to be updated by redstone block due the signal strength of the dust not being changed by the redstone block.