diff --git a/src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Repositories/SiteCallAuditRepository.cs b/src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Repositories/SiteCallAuditRepository.cs
index 115bb61a..4e829286 100644
--- a/src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Repositories/SiteCallAuditRepository.cs
+++ b/src/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase/Repositories/SiteCallAuditRepository.cs
@@ -196,19 +196,40 @@ public class SiteCallAuditRepository : ISiteCallAuditRepository
         // rethrown at the end, so the caller sees the same exception the old per-row
         // loop surfaced (and keeps its cursor), minus the collateral of the rows behind it.
         System.Runtime.ExceptionServices.ExceptionDispatchInfo? firstFailure = null;
-        for (var offset = 0; offset < siteCalls.Count; offset += UpsertManyChunkSize)
+        // Rows UpsertAsync would reject before touching the database (a null row, an
+        // unknown status) are validated up front and SKIPPED with their failure captured,
+        // so one malformed row cannot stop the rest of the page from applying.
+        var valid = new List<(SiteCall Row, int Rank)>(siteCalls.Count);
+        foreach (var siteCall in siteCalls)
         {
-            var chunk = siteCalls.Skip(offset).Take(UpsertManyChunkSize).ToList();
+            try
+            {
+                if (siteCall is null)
+                {
+                    throw new ArgumentException("A null SiteCall row was supplied.", nameof(siteCalls));
+                }
+
+                valid.Add((siteCall, GetRankOrThrow(siteCall.Status)));
+            }
+            catch (ArgumentException invalid)
+            {
+                firstFailure ??= System.Runtime.ExceptionServices.ExceptionDispatchInfo.Capture(invalid);
+            }
+        }
+
+        for (var offset = 0; offset < valid.Count; offset += UpsertManyChunkSize)
+        {
+            var chunk = valid.Skip(offset).Take(UpsertManyChunkSize).Select(v => v.Row).ToList();
+            var ranks = valid.Skip(offset).Take(UpsertManyChunkSize).Select(v => v.Rank).ToList();
             var sql = new System.Text.StringBuilder();
             var parameters = new List<object>(chunk.Count * 15);
             for (var i = 0; i < chunk.Count; i++)
             {
-                var siteCall = chunk[i] ?? throw new ArgumentException("A null SiteCall row was supplied.", nameof(siteCalls));
-                var rank = GetRankOrThrow(siteCall.Status);
+                var siteCall = chunk[i];
                 var suffix = "_" + i.ToString(System.Globalization.CultureInfo.InvariantCulture);
                 sql.AppendLine(SuffixParameters(InsertIfAbsentSql, suffix));
                 sql.AppendLine(SuffixParameters(MonotonicUpdateSql, suffix));
-                foreach (SqlParameter p in BuildUpsertParameters(siteCall, siteCall.TrackedOperationId.Value.ToString("D"), rank))
+                foreach (SqlParameter p in BuildUpsertParameters(siteCall, siteCall.TrackedOperationId.Value.ToString("D"), ranks[i]))
                 {
                     p.ParameterName += suffix;
                     parameters.Add(p);
diff --git a/tests/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase.Tests/Repositories/SiteCallAuditRepositoryTests.cs b/tests/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase.Tests/Repositories/SiteCallAuditRepositoryTests.cs
index 6d263a47..f6a2c6a7 100644
--- a/tests/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase.Tests/Repositories/SiteCallAuditRepositoryTests.cs
+++ b/tests/ZB.MOM.WW.ScadaBridge.ConfigurationDatabase.Tests/Repositories/SiteCallAuditRepositoryTests.cs
@@ -1018,6 +1018,40 @@ public class SiteCallAuditRepositoryTests : IClassFixture<MsSqlMigrationFixture>
         Assert.Equal("Submitted", stored.Status);
     }
 
+    /// <summary>
+    /// Verifies that a row with an unknown status does not stop the rest of the page: every
+    /// valid row is applied and the unknown-status failure is rethrown at the end (adversarial
+    /// review of 06/PERF-2).
+    /// </summary>
+    /// <returns>A task that represents the asynchronous operation.</returns>
+    [SkippableFact]
+    public async Task UpsertManyAsync_UnknownStatus_StillAppliesTheRestOfThePage()
+    {
+        Skip.IfNot(_fixture.Available, _fixture.SkipReason);
+        var site = NewSiteId();
+        var good1 = TrackedOperationId.New();
+        var bad = TrackedOperationId.New();
+        var good2 = TrackedOperationId.New();
+        var page = new List<SiteCall>
+        {
+            NewRow(good1, site, status: "Submitted"),
+            NewRow(bad, site, status: "NotAStatus"),
+            NewRow(good2, site, status: "Submitted"),
+        };
+
+        await using (var context = CreateContext())
+        {
+            await Assert.ThrowsAsync<ArgumentException>(
+                () => new SiteCallAuditRepository(context).UpsertManyAsync(page));
+        }
+
+        await using var read = CreateContext();
+        var repo = new SiteCallAuditRepository(read);
+        Assert.NotNull(await repo.GetAsync(good1));
+        Assert.NotNull(await repo.GetAsync(good2));
+        Assert.Null(await repo.GetAsync(bad));
+    }
+
     private ScadaBridgeDbContext CreateContext(DbCommandInterceptor interceptor)
     {
         var options = new DbContextOptionsBuilder<ScadaBridgeDbContext>()