Why is my SharePoint file not opening the latest version for the user?

We have a couple of linked shared SharePoint excel trackers. I was asked to make some changes ( new list dropdowns, update a formula). I would make the changes, save, and users kept complaining about things being broken, cannot update links messages etc.

So today I pulled the files offline, fixed everything, locked with password (sheet and workbook), and locked the ranges.

I archived the original files and replaced them with my local version. Then I asked the user to open it, bam old version, autosaves over my file. Replaced again. asked them to right click from the online folder to open, old version. click directly on SharePoint link to open in browser, old version. In the end I was so annoyed I renamed the files.

Obviously my prev changes were getting partially or wholly overwritten by other's files, but I am not sure what was happening today. How do you ensure to open the latest version of the file? Did they possibly have a hidden version open in a browser or something that was affecting the opened file?