When using the function "Explore page in Visual Studio Code" the "application version" in the app.json is set by the version of the installed "AL Language Extension". So in upgrade slots when SaaS has two possible running versions for environments or when you have activated the preview path you have an issue and must fix it manually to download the symbols

It would be better that the application version is set by the source environment the same way as you set the other extensions.

The same issue appears when using the function of "attach debugger" to the BC session. Debugging works as long as you do not need to dive into symbols.