Playframework: Strange Beginning Behavior - Caching Problem?

I am currently developing a web application using play framework 2. I have created a “files” folder in the / public directory. All resources in this directory were available when I start the server using "play run".

After deployment to the server. I started the server by running "play start" and found that the resources under the "files" could no longer be found.

I wonder what the reason for the inconsistency between the "start of the game" and the "game."

UPDATE: After a few samples. I found that a new loaded resource could not be displayed. The scenario is as follows:

1. play start --> server starts.
2. use application to upload a few images to the server.
3. try to display the uploaded image --> nothing is shown. browser shows the resource is not accessible.
4. kill the server process with task manager.
5. rm RUNNING_PID
6. run play start again 
7. Try to display the uploaded image --> now the images are showing.

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