ligtning rod doesn't break when the block that is attached to it is broken

works as intended?

I would also say that is intended as you can also place them not connected to anything like most MC-blocks. What goes up in Minecraft does (mostly) not come down.

Works as intended because the lightning rod is very similar to the end rod and behaves almost identically in terms of placement

Maybe it was meant to be? I mean, the End Rod doesn't break when there's no block under it, either.

So the Same With Candles, This Might Be A bug, But End Rods Don't Break

Can confirm that this is an issue, however, this is most likely intentional. Also affects 20w51a.