Object › Rasterize replaced a frame of threaded text by an image of
it. The thread's re-flow then added the frame's text to the story, as
it does for a frame that was deleted, so the other frames held that
text a second time while the image drew it.
A frame that Rasterize turns into an image now leaves its thread with
the text it shows, and the other frames keep the text they hold, as
with Create Outlines and Expand. When the thread's last frame is
rasterized, the text it has no room for goes after the text of the
last frame that stays. A thread left with one frame is no longer a
thread, and undo restores the thread.
Docs: docs/mcp.md, docs/target-app-parity.md.