Yes, with burst enabled in cases where customer using 100% of upload or download you can see packet loss on high priority channel due to way burst buckets refill. We did some pretty extensive testing and found these were only settings on 13.x firmware that wouldn't result in packet loss during max uplink or downlink usage by the sm.
This may of changes in 15.x someone at cambium mentioned they we're redoing the bucket scheduler to smooth things out a bit. Tim