Constant neighbor advertisements normal or not?

Hello,

Examining wireshark capture from another PC on the LAN shows a Raspberry Pi (running Raspbian) is constantly sending icmpv6 neighbor advertisements on the network. Three of them every 8 seconds, to be precise. The NAs have the override flag set and according to RFC 4861 (the Neighbor Discovery RFC for IPv6) the override flag is set to signal receiving devices to update their link-layer address caches with the address of the sender. As with all NAs the destination is ff02::1

Is this normal behavior? No extra daemons are running on the rpi, it is just a default installation of raspbian. It is the only ipv6 enabled device (homelab) that is doing this.

Thanks!