I got a beaglebone back from RMA center and when I go to plug it in via usb it the power light turns on for a little more than a second then powers off. However when i plug it in through the barrel jack it fine. I don’t know if this is safe or not for my beagle? If not what should I do?
Also when the ethernet is plugged in, its the leds alternate suspect something is wrong with the board i got.
Running on DC ony will not damage the board. It is designed to work that way.
It could be the USB source you have does not have enough current to power the board during the initial power up. You could try another PC USB connector.
As t Ethernet there could be connection issue.
If you want, you can respond back to the last email you received and let them know the board still has issues. They will take care of it.
Gerald
Yeah, it also shuts down when I have usb, ethernet and DC connected. So I think I might have to write an email. 
Thank you Gerald for your reply.
And I saw that you did.
Gerald