There is a moment between requesting a new page and having it rendered where it actually does not exist (i.e. a legitimate 404).
However, Experience Manager can handle this moment through a configured "blank" page, delivered through the root folder of your Staging site.
See the Documentation for instructions for creating a blank se_blank.html to avoid such ...
In your example you mention one base URL (corresponds to Website in TTM terminology), but you mention two CD Environments: STG and LIVE.
These two CD Environments should have distinct Websites (base URLs). Furthermore, each Website has at least one WebApplication (often only a root WebApp, so that the URL of the WebApp is the same as the base URL of the ...
The Topology subject can be, and is, complicated, especially for someone who is new to it. The best way to learn it is to simply play around with it and try to "feel" how the concepts relate to each other.
Now there are a lot of resource, blogs, etc. out there, but I find the following one very useful. If you have earlier experience with Tridion, then this ...
What you describe in your last comment is the normal behavior when the Session Preview is turned off or is not working properly. I have witnessed the exact same flow when I'd manually turned off Session Preview (as part of an earlier investigation on a project).
So... as Rick mentioned, check your Session (Preview) setup. This includes the required ...
AFAIK - CIL - Java Caching
Time based caching, NO invalidation
Limited OOTB config
Up the heap size by MB, not by entries
<?xml version="1.0" encoding="UTF-8"?>
I'm afraid this will be pretty hard to achieve, if at all possible. The cd_core log file of the deployer will contain a more helpful message (although in the form of a warning, there is no error logged at all in this scenario, which I find odd). But I wouldn't know how to present this message to the editor.
Couldn't you focus on preventing this situation in ...