Buffer bloat is when your router can't satisfy all connections with the full speed because the buffers are full with data. It's a form of congestion and usually caused by upload (!) congestion because the ACK packets can't be sent fast enough.
A possible remedy is using QoS and traffic shaping as well as bandwidth limits.
Download/upload a large file and monitor your ping to a random server in the internet while you do that.
traffic-control smart-queue FixUploadBuf {
upload {
ecn enable
rate 42mbit
target 40
}
wan-interface eth2
}