Problem with multiple PPPoE connections from same CPE to Tower.

Hi Guys

I work for a WISP.

I have a problem where a multiple PPPoE connections gets established from a single CPE sometimes up to 4 connections.
Problem is the connections drops and re-establishes after a few seconds over and over again.

What could be causing this?
It does not happen often though.

Please help.

Looking forward to your response.