  The family of smooth Fano 3-folds with Picard rank 1 and anticanonical volume
4 consists of quartic 3-folds and of double covers of the 3-dimensional quadric
branched along an octic surface. They can all be parametrised as complete
intersections of a quadric and a quartic in the weighted projective space
$\mathbb{P}(1,1,1,1,1,2)$, denoted by $X_{2,4} \subset \mathbb{P}(1^5,2)$; all
such smooth complete intersections are K-stable. With the aim of investigating
the compactification of the moduli space of quartic 3-folds given by
K-stability, we exhibit three phenomena: (i) there exist K-polystable complete
intersection $X_{2,2,4} \subset \mathbb{P}(1^5,2^2)$ Fano 3-folds which deform
to quartic 3-folds and are neither quartic 3-folds nor double covers of quadric
3-folds - in other words, the closure of the locus parametrising complete
intersections $X_{2,4}\subset \mathbb{P}(1^5,2)$ in the K-moduli contains
elements that are not of this type; (ii) any quasi-smooth $X_{2,2,4} \subset
\mathbb{P}(1^5,2^2)$ is K-polystable; (iii) the closure in the K-moduli space
of the locus parametrising complete intersections $X_{2,2,4} \subset
\mathbb{P}(1^5,2^2)$ which are not complete intersections $X_{2,4} \subset
\mathbb{P}(1^5,2)$ contains only points which correspond to complete
intersections $X_{2,2,4} \subset \mathbb{P}(1^5,2^2)$.
