There is no cake item drop if a block underneath is broken

Might be intentional, after all, you can't pick up the cake normally either. And what would a half-eaten cake drop?

Cake items never dropped, whether you broke them by hand or by removing blocks underneath it.

I also thought what would happen to only a partial cake. But that's up to Mojang to resolve... They might set that only a whole cake would produce drops.
I know cakes never dropped, regardless of how You tried to get it, but that's what I mean - isn't this technically a glitch (hence I mentioned it here)?

After placing the cake, you never been able to pick it back up.