Are you importing these videos into VP? Were the recently shot clips made by a different camera then those created earlier? What camera?
Please share a video clip or two that doesn't display and someone will check them out.
Upload the file/s to a free server, such as Google Drive or MS OneDrive, right-click the link and Share or Copy. Copy the result and paste it here or to me in a Private Message via the mail envelope in the top-right corner of this forum. When using Google Drive, click SHARE | SHARE and change "restricted" to "anyone with link can view.**
Or share the link privately with a message to me, by clicking the envelope at the top-right of this forum.