cannot mount/first aid USB drive

[BK_xyz]

I have a brand new SanDisk 512GB ultra dual drive go USB type-C flash drive. I formatted it exFAT and started using it, no issues. I have been transferring files from a Synology NAS to the USB via a mac-mini. The mini froze. I unplugged it, plugged it back in and started it up again. Since this reboot I cannot mount the drive or run a first aid. It is shown in disk utility but is greyed out. I tried my macbook and get the same result. Is it bricked or is there a fix? Any help would be appreciated. Some screen shots of the errors.

 

[BK_xyz]

and just like that its back!! Right after posting this I went into finder and there it was.