I've only just modded my Wii and ripped my collection of games. This morning, 3rd January 2021, three titles (out of 14) from my library were missing in USB Loader GX:
They all showed up and worked fine yesterday. Tried reconverting the ripped ISOs to WBFS (using Wii Backup Manager), but the titles were still missing.
On a hunch I set back the Wii clock back one day, to 2nd January, and the titles re-appeared. Corrected the date and the titles went missing again.
Now set back the date 20 years, so I should be good for now. But if anyone were actually relying on the date to be correct for other apps, it might be a problem for them.