Default graffiti used instead of custom one.

[lystopad]

Describe the bug
Default graffiti value used for published blocks, even when -graffiti=... flag set.

To Reproduce
Steps to reproduce the behavior:

1. Platform details (OS, architecture): 'Ubuntu 24.04.3 LTS, amd64'
2. Branch/commit used: 'docker image statusim/nimbus-eth2:amd64-v25.9.0'
3. Commands being executed:
   docker-compose.yml with command lines:

      command:
        --data-dir=/data
        --jwt-secret=/jwt-secret
        --el=http://execution:8551
        --web3-url=http://execution:8551
        --light-client-data-serve=true
        --light-client-data-import-mode=full
        --tcp-port:9000
        --udp-port:9000
        --graffiti="custom-graffiti"
        --rest
        --rest-address=0.0.0.0
        --rest-port=12345
        --network=hoodi
        --log-file=/logs/consensus.log
        --history=prune

5. Relevant log lines:
   Following logs printed after start:

{"lvl":"INF","ts":2025-09-03 18:25:38.619+00:00,"msg":"Launching beacon node","topics":"beacnde","version":"v25.9.0-660ebe-stateofus","bls_b
ackend":"BLST","const_preset":"mainnet","cmdParams":["--data-dir=/data","--jwt-secret=/jwt-secret","--el=http://execution:8551","--web3-url=http://
execution:8551","--light-client-data-serve=true","--light-client-data-import-mode=full","--tcp-port:9000","--udp-port:9000","--graffiti=custom-graffiti","--rest","....

For the sent block I see:

...{"deposit_root":"00000000000000000000000000000000000000000000000
00000000000000000","deposit_count":0,"block_hash":"0000000000000000000000000000000000000000000000000000000000000000"},"graffiti":"Nimbus/v25.9.0-660ebe-stateofus"

But why not expected graffiti custom-graffiti?

Here you can see a lot of blocks proposed by different proposers but having the same graffiti.