Maybe it's overheating? I personally do not recommend that style of USB readers due to the MicroSD card being close to the front USB ports, which are notorious for being very hot.
I've always recommended something with the reader away, such as https://www.amazon.com/dp/B01EFPX9XA
I have always recommended this combo (paired with a High Endurance MicroSD).
However, if Tesla continues its development to allow more video streams to dump to the USB drive (currently there are *4* video streams being written), I'm most likely going to change my recommendation to a USB SSD, ex: