WHEN IT SURFACES

Nobody remembers the same session.

Memory is not a reliable record of authorship, and it gets less reliable in exact proportion to how much money is involved.

The registered writer	Genuinely believes they wrote it, and has two years of being told they did.
The others	Equally sure of their contribution, with no way to demonstrate it beyond their own account.
The evidence	A group chat, some voice notes, a project file with somebody else's name on it.
The outcome	Either an uncomfortable settlement or the end of a working relationship. Usually both.

The people best placed to fix this are the four who were in the room, on the night, before it mattered.