One of my colleagues observed the same behavior on a V12.3.2 backup server today.
However, notification emails from our V13 Windows and Linux backup servers appear to be correct (english).
I suggest waiting a few days to see if it returns to english — it might just be a temporary hiccup in Microsoft’s Exchange Online detection services.
Re: #MOD: Picture link updated - did you have to make a edit for the image to appear. Using imgbb was suggested in another post but it didn't appear to work for me.
The language issue isn't a show stopper at all. Haven't a clue why Exchange Online (I assume) would think it's Japanese.
I opened https://ibb.co/Jjrmpk0h and extracted the direct link from the image, then used IMG tags with that link.
Haven't a clue why Exchange Online (I assume) would think it's Japanese.
Me neither — I checked the source code of one of the emails, and there was no indicator for a Japanese charset.
That’s why I suspect it’s something temporary on the Exchange Online side.