I suspect shaper because it is egress traffic.
vlan-id rate limit should be as far as I know egress direction only.
Example Config
/interface ethernet switch rule
add ports=ether1 switch=switch1 vlan-id=123 rate=10M
Is rate=10M a policer or shaper?
For > ingress > traffic QoS > policer > is used, for > egress > traffic QoS > shaper > is used.
https://help.mikrotik.com/docs/display/ROS/QoS+with+Switch+Chip