And calling this "solvable" is a funny thing to think about, since huge portions of the earth think the chaos output of LLMs could be anywhere near deciding the final output of computation at this point in time
Agreeing on edits requires a shared context, a shared understanding of the goal and requirements of the text being edited, and a shared projection of how readers should understand the text and how they will understand it instead.
The specific contextual information required for automated editing is dependent on the combined situation of all writers, considering their professional, personal and cultural contexts.
Assuming that context can't be made available in a systematized way, the machine will choose an edit that is not guaranteed to match the intentions and expectations of the people involved. Instead, it will just act as adding one more writer to the mix.
You say this word is only required if it's a part of this whole sentence? OK, the other edit kept the whole sentence, but changed a single other word in it, which happened to be the subject.
The given situation is solvable only by the humans involved. They want different things. Either one of them has authority over the other, or they talk it over.