The file you are seeing, with a .crdownload extension, is a temporary placeholder created by Google Chrome (or other Chromium browsers) while a file is actively downloading.
Instagram’s servers may have timed out or limited the connection during the download. ✅ How to Fix and Get Your Video You can usually recover the video without starting over: How to resume download from .crdownload file? : r/chrome
Chrome often labels downloads from social media as "unconfirmed" if it deems the source potentially insecure or if it needs you to manually "Keep" the file.