Take a minute to share a file or two that does this and someone here will check it out. 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."
Several HEVC video-only files were tested here in version 10.24 64-bit and all played normally.