I do not think it is a name conflict problem.
The above two simulation was not the same. Because there are related to different jar file.
If there are more than one place in this forum where the uploaded jar file are the same name,
all the post will be shown the same simulation (because they all referer to the same jar file).
So when I update a new version of the same jar, I will modified original posted message and upload it again. (You will find [b]update EJS jar file option[/b] instead of [b]upload ejs jar file option[/b]) (may be only moderator can modify message after there is a replied message). But you can modified it (upload jar file again) if it is the last message in the same topic. Or, may be I can create a new board for you (so you become moderator for that board. How about this ideas!)
I think the problem you saw is due to your browser did not load a new jar file from the server but use cached file in your computer when you view it again.
If you already view a simulation with your browser , and upload new version later on, then your will find the loaded simulation did not change. Because browser did not load latest version (but use cached file instead).
You will need to close browser window (shut down browser program completely).
Then re-start the browser to view the new version.