I wrote:
Jeffrey Walton replied:
Throw the old SDcard away, and use a new one.
I intend to. But this isn't a problem with the card.
Samuel Sieb answered:
Are you sure? It does sound likely. e2fsck doesn't write without warning. I suggest testing it with the f3 tools.
"e2fsck -c" said it didn't find any bad blocks. If it didn't find any, why would it modify the card at all? "e2fsck -y" (by itself) did not report any problem.
I agree the card seems flaky and I've already ordered a replacement. But I remain concerned by the result of using -c; that doesn't seem related to the problems with the card since it claims not to have found any bad blocks.