Forum:"One might suppose that Homer nodded": A Question Concerning Christopher Tolkien's Commentary on 'The Drowning of Anadûnê'

The answer to this question will likely require familiarity with the works of Homer in addition to the contents of The Silmarillion. I don't have much more than a basic knowledge of the former, but maybe someone here does.

Part III of Volume IX of The History of Middle-Earth (hereafter HME) series by Christopher Tolkien (hereafter C.T.) is titled "The Drowning of Anadune" and concerns versions of the Numenorean legend. The story is told from a "mannish" perspective, as though the author were a man living in the Third Age or later, so certain details are intentionally muddled or unclear. The writing dates to about 1946, so as yet none of the content that would later become The Silmarillion had been published, and J.R.R. Tolkien (hereafter Tolkien) was still experimenting with various elements of the mythology.

In "The Drowning of Anadune," one of the details that is left vague is the geography of the westernmost lands of Middle-Earth prior to the changing of the world after the rebellion of the Numenoreans. Tol Eressea in particular is not named in these versions of the Numenorean story. Yet Avallone is, under various spellings. In a narrative sketch from this time, Tolkien recorded the idea that the Numenoreans were at one time allowed to visit Tuna, or Tirion, upon a hill behind the haven of Avallonde.

As we know now, of course, the spelling of Avallone would eventually be thus (minus diacritical marks which I cannot figure out how to insert in this field in the proper font), and Tirion upon Tuna would become a city of the elves in Valinor, not on Tol Eressea where was Avallone. But in the context of the writing of "The Drowning of Anadune," not all such questions were settled in Tolkien's mind, and the narrator of these versions of the Numenorean tale would not necessarily have been aware of the true state of things even if Tolkien himself was.

My present question, however, is not related to the content of the story per se, but to something that C.T. wrote in his analysis of the story. I will quote from HME Vol. IX, Part III, part v, footnote 16:

"A curious case is presented by the statement in Sketch III, p. 403, that 'the city of [Tuna>] Tirion' was 'on the hill behind the haven of Avallon(de)'; for Tun(a), Tirion was of course the city of the Elves in Valinor.  One might suppose that Homer nodded here; but in the earliest draft of an Old English text for 'Edwin Lowdham's page' (p. 316). . . it is told that the Numenoreans, landing in Valinor, set fire to the city of Tuna.  The statement in Sketch III is therefore more probably to be taken as intentional, an example of a famous name handed down in tradition but with its true application forgotten."

What does C.T. mean by "One might suppose that Homer nodded here"? The context for this comment, simply put, is that the location of a city has just been erroneously given. What could the relevance of this fact be to Homer or to Homeric sagas?

I am curious because I am interested in myths and in ancient history generally, but explaining this context to Homer fans who are not also deeply familiar with Tolkien would be too complicated. Therefore I seek here for fellow Tolkien fans who may be familiar enough with Homer to shed some light on C.T.'s comment.