Windows v 184.108.40.206
The calendar is no longer showing images for entries from later in the day as the thumbnail.
Currently, if the first entry of the day has a photo, it will show that as the thumbnail for the day. However, if the first entry of the day doesn't have a photo, the thumbnail no longer shows the next available photo from the day like it used to.
I'm assuming this is a bug and not a new feature.