Post removed from blog category listing page after meta & social update

Hi!

I've checked several installations of Perch 3.1.1 & Runway 3.1.1 with Perch Blog 5.6.1 & behaviour is the same. Here are the steps:

1. Create blog post, assigned to any blog category & publish
2. Check category listing page - post is listed.
3. Update the post from the Meta & Social tab, i.e. add some tags, update author, etc & save
4. Check / refresh category listing page - post is gone (but correct checkboxes are still checked on the post content tab)

For the post to show up on the category listing pages, it has to be saved again from the blog content tab - Is this a known bug?