The grid (core) · console.warn

selection is being tracked by index because ...

Printed by The grid (core), prefixed [lattice], since 1.0.1.

Warnings reference › selection.unstable

Identifier: selection.unstable
Raised by: The grid (core)
Since: 1.0.1

What happened

With no rowKey the selection is a set of positions rather than a set of rows. Sorting, filtering or reloading moves the rows and leaves the positions where they were, so the user finds different rows selected than the ones they chose.

The fix

Configure rowKey.

Reference

Covered in full at the API reference.