When a .ai's layers can't be read from its editing data yet, it opens as
its PDF part, which lists the artboards as pages; those were laid out in
a row, so a grid of artboards (or any other arrangement) was lost. The
editing data's artboards are now read even then (ai::artboards, as far
as the reader gets) and, when there are as many as pages and of the same
sizes, each page goes where its artboard is, with the art on it (the art
of a page: the objects mostly on it, else nearest it). Otherwise the
pages stay in a row as before.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>