RB750 Drops PPOE clients when cable unpluged

ether1 is connected to internet provider’s cable modem
ether2 is connected to PPOE client
ether3 is connected to laptop running Winbox

PPOE clients will be running perfectly fine and Winbox is running fine. I then unplug the cable from ether3 and the PPOE clients loose connection. Why does unplugging from ether3 cause issues with ether2?

It is very depend on your configuration
I think you use layer 2 config ,
Please send your configurations