A number of bloggers are reporting that their post text was moved into the photo caption area.
In March 2014 we made an improvement to the posting process that allows you to include text between photos. Originally, there was one text area to describe your project on the top of the post and the only other way to add text was as a caption to a photo. So the way that many people wrote their posts was that they included the steps to their project in the photo captions. Since the photo captions were displayed below each photo, this made sense. The user would read the the project description on top, and then scroll down and follow the project steps in the photo captions.
In March 2014 we added the ability to include post text in between photos, so that you can continue to describe your project as the reader scrolls, and you don’t have to write photo captions to do so.
In January 2016 we changed the way that we display photo captions. Instead of showing the caption for a photo under the photo, we now display it on (overlaying) the photo. This makes it clear to the reader that the text is actually a caption for the photo and not part of the post text, and allows them to differentiate more easily between captions and the actual post.
Since posts that were created before March 2014 often had their description in the photo caption, this design change made it look like the post text was removed and made into a caption, even though in reality it was always a caption.
In terms of the 100-word requirement to include a link at the bottom of your post, photo captions were never included in the word count. This never changed and was not affected by any of the updates listed here.