source.mode "derived": `statistics: { fn: 'series' }` needs both `of` (the column to summarise) and `by` (the column that orders it). `by` is never guessed - kernels see rows in arrival order, which is not the grid's sort.

Warnings reference › source.derived.statistics.series

Identifier

source.derived.statistics.series

Raised by

The grid (core)

Since

1.52.0

What happened

A series statistic summarises one column along the order of another, and one of the two is missing. The order is never guessed: the kernels see rows in arrival order, which is not what the grid is showing, so a guessed order would silently produce a different series from the one on screen. Nothing is produced.

The fix

Name both of and by.

Reference

Covered in full at the API reference.