node failure when adding new nodes to existing network with `blockStream.streamMode` set to `BOTH`

After changing from from `blockStream.streamMode=BOTH` to `blockStream.streamMode=BLOCKS`
on the `application.properties`, new nodes added to the network started producing error message and not starting.

Log message from `/opt/hgcapp/services-hedera/HapiApp2.0/output/swirlds.log`

```
2025-11-06 15:18:37.313 67 ERROR EXCEPTION DefaultSignedStateSentinel: Old signed state detected. The most likely causes are either that the node has gotten stuck or that there has been a memory leak.
null
```

relates to:
- https://github.com/hiero-ledger/solo/issues/2842

Start with the configuration change in application.properties and the related Solo issue, then inspect the reported output/swirlds.log entry from DefaultSignedStateSentinel. Reproduce adding nodes after changing blockStream.streamMode from BOTH to BLOCKS and trace why the new nodes fail to start. Done means the failure cause is identified and newly added nodes start successfully after the configuration change.

Written by the indexing model from the issue text.