according to a similar post Plug.Static is unable to serve files in production - #8 by OvermindDL1
this could be that the path for plug static is resolved at compile time
plug Plug.Static, at: “/downs”, from: Path.expand(‘./downs’)
so the . is the directory where the release was built, so when moving the release to another directory, it does not work anymore
but that does not explain why file1 is found and not file2
