Pls note that the fixed rate limiting applies to all traffic on the rate limited port. It counts the number of bytes that a port receives in one second intervals. If the number exceeds the maximum number you specified when you configured ...
Pls find the documentation link for enabling BUM suppression logging and ensure you have configured it right.
On ICX, A port can be untagged on any single vlan and tagged to multiple vlans. This is the thumb rule. You can open a support case to have a quick call with support staff to clarify your questions as well.