I have had a couple secret Lairs that I added not show a price with the foil. They do have a foil version, and it shows it on the card page, but when you add it to inventory it just says NA instead of displayng the foil price its get from TCGplayer. Elenda, Thje Dusk Rose (SLD 1411) can be used as an example.

I know Sebi and his team have a whole slew of cards like this on a list, not just Secret Lair cards, that they are working on. I have a bunch in my inventory.

Makes sense, I just noticed it today. Reorganizing and redoing my inventory since I never kept up with and so adding alot of cards, finding things I didn't know about on the site while doing it haha.