The symptom [0]:
Initializing rx queues on lcore 1 ...
Initializing rx queues on lcore 34 ... rxq=0,0,1 mlx5_net: port 0 Rx queue 0: Scatter offload is not configured and no enough mbuf space(2176) to contain the maximum RX packet length(9200) with head-room(128)
mlx5_net: port 0 unable to allocate rx queue index 0
EAL: Error - exiting with code: 1
Cause: rte_eth_rx_queue_setup: err=-12, port=0

Not sure CSIT just needs to configure more mbuf space, or it is some deeper issue (as 9000B l3fwd generally passes on other NICs).
Testpmd appears to start normally (which may be another issue), but then forwards zero packets.

[0] https://s3-logs.fd.io/vex-yul-rot-jenkins-1/csit-dpdk-perf-report-coverage-2306-2n-icx/2/log.html.gz#s1-s1-s1-s4-t6-k2-k4