Mirror node acceptance tests fail post-restart with "No network stake data found" during mainnet migration test

Summary

During mainnet migration testing (0.74.3 → 0.75.1, staging-lg environment), mirror node acceptance tests failed post-restart with:

org.springframework.web.client.HttpClientErrorException$NotFound: 404 Not Found: "{"_status":{"messages":[{"detail":"No network stake data found","message":"Not Found"}]}}"

Reran the tests a second time — same error.

Root Cause (suspected)

Migration test froze the network before midnight and restarted it after midnight. A WRB migration took place around that boundary.

Consensus-node observability data (see Diagnostics below) shows migration root hash voting finalized successfully and staking-period reward/fee processing ran without error around the restart, so this does not currently look like a consensus-node halt or crash. It's still unconfirmed whether a NodeStakeUpdate record/block was actually published during the affected run, or whether this is a mirror-node ingestion gap.

Rerunning the migration test with freeze/restart entirely after midnight (i.e., not spanning the midnight boundary) passed without the No network stake data found error.

Environment

• Upgrade path: 0.74.3 → 0.75.1
• Environment: staging-lg
• Failed stage: Post-Restart Validation / Acceptance Tests

Diagnostics

Failing scenario:

ERROR ... o.h.m.t.e.a.s.NetworkFeature Scenario failure:
I verify the network stake <- 404 Not Found: "{"_status":{"messages":[{"detail":"No network stake data found","message":"Not Found"}]}}"
 org.springframework.web.client.HttpClientErrorException$NotFound: 404 Not Found: "{"_status":{"messages":[{"detail":"No network stake data found","message":"Not Found"}]}}"
	at org.hiero.mirror.test.e2e.acceptance.client.MirrorNodeClient.getNetworkStake(MirrorNodeClient.java:374)
	at org.hiero.mirror.test.e2e.acceptance.steps.NetworkFeature.verifyNetworkStake(NetworkFeature.java:37)
	at ✽.I verify the network stake(classpath:features/network/network.feature:6)

Test run summary:

Failures (1):
  JUnit Platform Suite:AcceptanceTest:Cucumber:Network Coverage Feature:Get network stake
    ClasspathResourceSource [classpathResourceName = 'features/network/network.feature', filePosition = FilePosition [line = 5, column = 3]]
    => org.springframework.web.client.HttpClientErrorException$NotFound: 404 Not Found: "{"_status":{"messages":[{"detail":"No network stake data found","message":"Not Found"}]}}"

[        75 containers found      ]
[         0 containers skipped    ]
[        75 containers started    ]
[         0 containers aborted    ]
[        75 containers successful ]
[         0 containers failed     ]
[        45 tests found           ]
[        20 tests skipped         ]
[        25 tests started         ]
[         0 tests aborted         ]
[        24 tests successful      ]
[         1 tests failed          ]

Consensus-node observability data for the staging-lg hosts during the freeze/restart window (23:40–00:45 UTC) shows no ERROR/WARN entries, migration root hash voting finalizing successfully (>1/3 threshold reached), and staking-period reward/fee processing running normally around the restart.

Full acceptance test log: acceptance-tests-45064.log

For more information, see the internal incident discussion: https://swirldslabs.slack.com/archives/C0BJWK4MQ2X

Reproduction status

• First occurrence: migration test freeze before midnight, restart after midnight — failed with No network stake data found.
• Reran freeze/restart entirely after midnight — passed without the error.

/cc @mhess-swl