backup: TestMergeTickEventsFromBackup failed

backup.TestMergeTickEventsFromBackup [failed](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Ci_TestsIbmCloudLinuxS390x_UnitTestsS390x/21466339?buildTab=log) with [artifacts](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Ci_TestsIbmCloudLinuxS390x_UnitTestsS390x/21466339?buildTab=artifacts#/) on master @ [b93cfbdc5d54c6d175ecfbc87bce7b004af9d03b](https://github.com/cockroachdb/cockroach/commits/b93cfbdc5d54c6d175ecfbc87bce7b004af9d03b):

```
=== RUN TestMergeTickEventsFromBackup
test_log_scope.go:172: test logs captured to: /artifacts/tmp/_tmp/cf44608303c9483f53cd355ec9615aa7/logTestMergeTickEventsFromBackup2140630391
test_log_scope.go:82: use -show-logs to present logs inline
restore_revision_log_test.go:358:
Error Trace: pkg/backup/restore_revision_log_test.go:358
Error: Received unexpected error:
unexpected marker "/log/resolved/2026-08-15/02-25.50.pb3191520776.tmp" under log/resolved/ (missing ".pb" suffix)
(1) attached stack trace
-- stack trace:
| github.com/cockroachdb/cockroach/pkg/backup.TestMergeTickEventsFromBackup.(*LogReader).Ticks.func2
| pkg/revlog/reader.go:148
| github.com/cockroachdb/cockroach/pkg/backup.TestMergeTickEventsFromBackup
| pkg/backup/restore_revision_log_test.go:355
| testing.tRunner
| GOROOT/src/testing/testing.go:2036
| runtime.goexit
| src/runtime/asm_s390x.s:864
Wraps: (2) unexpected marker "/log/resolved/2026-08-15/02-25.50.pb3191520776.tmp" under log/resolved/ (missing ".pb" suffix)
Error types: (1) *withstack.withStack (2) *errutil.leafError
Test: TestMergeTickEventsFromBackup
testutils.go:448: no Invalid Descriptors
panic.go:694: -- test log scope end --
test logs left over in: /artifacts/tmp/_tmp/cf44608303c9483f53cd355ec9615aa7/logTestMergeTickEventsFromBackup2140630391
--- FAIL: TestMergeTickEventsFromBackup (37.44s)
```
Help

See also: [How To Investigate a Go Test Failure \(internal\)](https://cockroachlabs.atlassian.net/l/c/HgfXfJgM)

/cc @cockroachlabs/disaster-recovery

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Jira issue: CRDB-66699