The mrvl_brg_port_stg_cist_init() message is reported into the system message file when an STP/RSTP/MSTP configured port is moved from one VLAN to another VLAN.
The mrvl_brg_port_stg_cist_init() message is logged each time VLANs are assigned to STP/MSTP/RSTP configured ports.
When a port is moved from one VLAN to another VLAN, the ASIC does a sanity check for the port states/BPDUs and other protocol related information, and it logs the action into the syslog.
Below is an example of the message. The port for which the assignment/reassignment was done and also its current state is listed. In this example, the state is CIST (MSTP) when the port is moved from one VLAN to another VLAN running MSTP.
MRVL-L2,mrvl_brg_port_stg_cist_init(),8972:CIST-State validated for IFL(ge-1/0/34.0,Idx=119)Oper-type=Best(2), STG-State=Blocking(1)"
The cause for such a notification is an ASIC sanity check that is performed each time VLANs are assigned to ports with any configuration of Spanning Tree Protocol or its variants like RSTP or MSTP.
Determine if the port mentioned in the log message is a configured STP/MSTP/RSTP port and was moved to a VLAN.
Using the CLI commands show spanning-tree interface and show vlans extensive, verify whether the port for which the message was logged is running the expected STP configuration and has been assigned to a VLAN.
This message is low priority, initialization warning message and is harmless; therefore it can be ignored.