Before loading a new project Clear Unused Cache Files, under OPTIONS | DISK tab.
Someone will come up with an answer if you take a minute to share an mp4 file or two that does this.
Just upload the file/s to a free server, such as Google Drive or MS OneDrive, get a shared (public) link, copy the link and paste it here or to me in a Private Message via the mail envelope in the top-right corner of this forum.
Using Google Drive, if necessary change "restricted" to "anyone with link can view."