Just to be clear, the comment about x of nine lives wasn't changed, diff is primarily used for comparing patches and so it includes context around what was changed. Only lines with a preceding --- or +++ were changed (which funk bolded).
The lines around the nine lives in Reisenjima are:
Around five out of nine lives rrremaining!≺Prompt≻
Around seven out of nine lives rrremaining!≺Prompt≻
Around three out of nine lives rrremaining...≺Prompt≻
I only compared 3 zones (Bastok Markets, East Ronfaure (S), Reisenjima), it looks like ~600 total files were changed, but the same line was changed in all 3. It's possible some zone in the list got changes the others didn't, but I don't have a programmatic way to export them all.
Disappointing for sure, but the real question is: why couldn't this have waited until the regular monthly update?
Probably going to kick off the event prior to next months update. It's also possible they pushed some server side stuff that wasn't accompanied by a client update.