Auto-update doesn't work for some users (sideloaded MSIX package)

We have a WPF app that our users are sideloading off our network with an MSIX package. We have it set up to pop up the update window when the program starts if there's a new update. However, there are a couple of users who don't get this window when they run the program.

I can think of one possible cause. We have been editing the C:\Program Files (x86)\Microsoft Visual Studio\2019\Professional\MSBuild\Microsoft\VisualStudio\v16.0\AppxPackage\Microsoft.AppxPackage.Targets file to get rid of the _Test suffix on the installation directory. There was a time where Visual Studio was updated and we forgot to change those and wound up making a few weeks of directories with the _Test on them, but most of them do not. Don't ask me why we got in this situation. Anyway, could that have an effect on it? Maybe these two use installed it when the directory was named _Test (but now the directories don't have that suffix)? We do weekly updates to the program and we have every version in a subdirectory. The MSIX package thing deploys it that way for us.

Another possibility is that I didn't discover the popup window feature until a few releases ago. Maybe if the user originally installed the app when the popup feature wasn't turned on, and we turned it on later it doesn't take effect?