Time to live exceeded in PPPoE authentication

We authenticate our clients through pppoe tunnel, and some times we face a little problem that every time is solved by just dropping the client session.. This was happening only some times, but today, almost every client authenticated in our pppoe concentrator is facing this problem..

I´m attaching some prints from our pppoe configuration

In the station radios, we use 1492 MTU/MRU. We bridge all port from CCR and create a local pppoe server in the bridge. We use CCR1009-8G-1S-1S+ and the hardware use is ok (CPU around 10,12%)
PPPOE.PNG