Plug in and plug out means the drive isn’t getting enough power.
@isolar801 – do you have an opportunity to swap the power supply to that device with another? Can you also show us a picture of the power supply that you are using currently and share it here so we can see specs?
The Vero will only provide 500ma to each attached device as per the USB 2.0 spec; if your cradle has a good power supply, this won’t be an issue. It seems like the drives however may not be receiving enough power.
Your comment makes sense re. drive access being attempted. Typically when we see these disconnects its because the drive is being spun up, but there is not sufficient power to keep it going so it spins down again. It may appear briefly as an accessible disk but this is not sustainable.
I’d wager that if you tried just one drive from the cradle, you’d probably see it; which would confirm a power problem