RT ax86u Repeated disconnection when ipv6 is active in pppoe mode

[Murat Y]

Hello. i am using ax86u pppoe mode with, a vdsl modem in bridge mode. but interestingly, when I activate ipv6, the connection is disconnected and reconnected every few minutes. already router, light is a red and a white blink.and this is repeated over and over. but when i turn off ipv6 there is no problem. Any idea where the problem originates from?