There can also be a lag in time from when the NetWeaver instance replicates files from the WEB portion of MII to the file system of the NetWeaver instance node (Did you know that all files hosted from NetWeaver have to be from the server filesystem?). This is how NetWeaver is designed to host files, not from the DB directly but from the filesystem. Sometimes this replication of files from the DB to the filesystem can take some time depending on the server configuration.
You can manually force a "Publish" of the content from the MII DB tables to the filesystem via this URL call:
http://<server><port>/XMII/Catalog?mode=blowout&Folder=<Project>/<Path>
Regards,
Sam
PS: I would also create a support ticket for this as the content should immediately be pushed to the file system when it gets created.