02-16-2019 12:48 PM - edited 02-16-2019 12:52 PM
The recent tab shows media temporarily held in the GoPro app for use to make Quik Story videos. If you select the media you have the option to save to your local (mobile device's) storage.
So the app doesn't end up consuming all of your device's storage space with unwanted media (if you don't save it locally its assumed to be unwanted), the app purges old media. If you sign up for GoPro Plus, the media in the recent tab gets uploaded and stored in the GoPro Plus cloud storage. If you don't have GoPro Plus or don't save the media locally, then the media is lost.
Hopefully you haven't overwritten the SD card with too much data and can recover the lost media. Best of luck.