Last post not showing unless I post again

Here is a fun one for you…

I am trying to display posts of a certain category in 2 different places. First, I have a sidebar widget in place (Miniposts) that will display the 10 most recent posts that match that category. I had this functionality working perfectly yesterday and I actually created about 15 posts to include in this to make sure only the 10 most recent were listed.

Today I am working on getting ALL of the posts of that category to display as a simple list on a page (not the front page). Once I got that working, I started adding more posts and immediately hit a snag.

When I create a new post, lets call it postA (add title, content, tags, category, etc.) and publish it, the new post will show in the admin panel (i.e. I can edit it, see it listed under the category I assigned, etc.) but it will not show up in either the sidebar widget, or the page list even though the other posts do show up even after refreshing the page and flushing the cache. Then if I create ANOTHER new post, postB, and publish it, postA shows up, but not B.

So it’s as if the functionality that grabs each post for displaying is somehow skipping the first post in the list. Any ideas what I might have borked up in my editing that would cause this behavior?