I'm using this post/thread to gather up any errata that have been found in the various History of Middle-earth volumes (print or eBook, any editions). If you know of any and want to add them here, please post them as a reply or send me a note. I will be adding more over the coming days/weeks as well.
The Book of Lost Tales Part I
In the poem titled "Habbanan beneath the Stars" the first line as published says "In Habbanan beneath the skies" - "skies" is a misprint, and should be "stars". Confirmed in two manuscript versions of the poem in the Bodleian archives that the first line in both is ‘In Habbanan beneath the stars’.
Do you want typos too or just genuine errors? I have a running list of the latter and a selective list of the former (of which BOLT has an unusually high number).
I find the transcription of the ultimate form of "Eärendel was a mariner" in The Treason of Isengard pp 103-5 is a little different from the manuscript reproduced in The Art of the Manuscript (2022) pp 80-3. The version reproduced in LR Reader's Companion pp 210-3 follows the description in TI, thus repeating all the inaccuracies in TI, plus a few more, as it uses the LR version for stanzas untranscribed in TI, whereas the LR version is different from almost ALL the available manuscript and typescript versions in the spelling of several words.
Stanza 1: Eärendil was a mariner It is "Eärendel" in MS.
Stanza 6: for ever king on mountain sheer; It is "Mountain" in MS. The same form is used in LR, so does another version reproduced in AM.
And here are LR's differences (which leads to inaccuracies in LRRC):
Stanza 3: from west to east; stanza 4: from east to west All versions transcribed in TI or reproduced in AM use the capitalized form “West” and “East”.
“The Elvenking’s Gate”
Stanza 8: and burning as an island star All versions transcribed in TI or reproduced in AM use the hyphen form “island-star” or “beacon-star”.
July
Stanza 9: of women and of elven-maids All versions transcribed in TI or reproduced in AM use the capitalized form “Elven-maids”.
“Lake Town”
I think the current forms in LR could be mistakes introduced during typesetting. Though we need check the proofs to be sure.