Tessa, I just had a revelation:
The photos in my galleries are being stored in the right month and year (02/12) but I couldn’t figure out why oh why the thumbnail would go into the 02/11 folder.
Well, it turns out that’s the month when I created that page. So naturally, every content I put in there (even if it’s linking to fresher content) will live in that particular folder.
I also went into Settings and checked to make sure that my WP getting the right date, and indeed, everything is working as it should.
It was just very disconcerting to see the same month but the wrong year! But just a coincidence it seems. Well, back to work. I hope this is helpful to all of you out there who make use of this Organize my uploads into month- and year-based folders feature!
Good luck! And if you want, check out our new gallery (the one I was having trouble with): https://villalobosbrothers.com/photo-gallery/fiddlers-on-the-roof/