I got an email from a school saying that my file was complete, BEFORE they even sent me the link with their secondary. I was a bit confused until five minutes later I got another email with the secondary. However, the school is notorious for sloppy and untimely admissions communications.
Yeah, that happened to me with Pritzker. They initially sent me a complete email before my MCAT score was even released. Then I think I got about three emails telling me they were waiting for my score (even though it had already been released to them and noted on their status page), then I got a faulty post-review hold email (they told me over the phone it was an error), and then finally a pre-interview hold several weeks after that.
At UIC, luckily they have a status page that shows which LORs they log in. They had me marked as incomplete because they didn't have my committee letter. In fact, they did. And when I called to point out that that was the ONLY LOR that was sent to them, they corrected it and marked me complete. Scary to think about that happening at schools that don't even have status pages.
Similarly, the status page at MCW told me I was complete around 7/20, but I received an email from their dean at the end of August telling me I was missing materials. I called up and they confirmed that I was complete, but that somehow it hadn't been logged correctly in the system. While they claimed that wouldn't impact when my app was reviewed - it clearly did. They review and give out interviews based on date of completion and app stats (per their own admission). And I saw people who were complete in July getting the "moved to to a smaller group of applicants that may bet an interview invite" at least a month before I received that notice, which was sent out the same day to people who had been complete in late August. In the end, it didn't matter since I chose to withdraw, but it does go to show that following up on each and every application is sometimes necessary to not fall through the electronic cracks.
I'm sure things like this happen at many, many schools. Scary.