The following thread has more details :
http://forum.mikrotik.com/t/crs354-48p-4s-2q-traffic-problem-on-ports-1-to-8/139024/1
No definitive solution as of 11/10/2020 
The following thread has more details :
http://forum.mikrotik.com/t/crs354-48p-4s-2q-traffic-problem-on-ports-1-to-8/139024/1
No definitive solution as of 11/10/2020