Steel Defenders are "biological" Constructs?

[Psyren]

It's not in the short description of Iron Defender, but a bit above, in the general blurb on homunculi. At least in the 1st printing.

Hot damn, you're right.

That line is also present in the Beyond version of ERftLW - but just like the printed book, it's not actually in the individual statblocks, it's part of the broader "Homunculus" preamble.