From my trial, these lateral crown emerge about two to three months after I planted runners to pots.
Like runners, these lateral crown are genetically same as the parent plant and this is one way of propagating strawberry plant quickly.
In the case of lateral crown, the entire strawberry plant cluster and the crowns are separated from parent rhizomes by carefully cutting it off. This process takes practice and could kill the mother plant if not done correctly.
It is good to have more than one crown in a pot, this will maximized the growing area and a normal practice for strawberry grower to do.
Below more photos of lateral crown at various stages of growth.