diff --git a/src/DataAccess/src/SIL.DataAccess/MemoryUpdateBuilder.cs b/src/DataAccess/src/SIL.DataAccess/MemoryUpdateBuilder.cs
index bbf6b5d9..4c537206 100644
--- a/src/DataAccess/src/SIL.DataAccess/MemoryUpdateBuilder.cs
+++ b/src/DataAccess/src/SIL.DataAccess/MemoryUpdateBuilder.cs
@@ -204,7 +204,23 @@ TField value
         (IEnumerable<object> owners, PropertyInfo? prop, object? index) = GetFieldOwners(entity, filter, field);
         object[]? indices = index == null ? null : [index];
         foreach (object owner in owners)
-            prop.SetValue(owner, value, indices);
+        {
+            if (owner is IDictionary dictionary)
+            {
+                if (index != null)
+                {
+                    dictionary[index] = value;
+                }
+                else
+                {
+                    throw new ArgumentException("Cannot set a field on a dictionary without an index.", nameof(field));
+                }
+            }
+            else
+            {
+                prop.SetValue(owner, value, indices);
+            }
+        }
     }
 
     private static bool IsAnyMethod(MethodInfo mi)
diff --git a/src/Serval/src/Serval.Translation/Services/TranslationPlatformServiceV1.cs b/src/Serval/src/Serval.Translation/Services/TranslationPlatformServiceV1.cs
index 29023e6a..14f1444c 100644
--- a/src/Serval/src/Serval.Translation/Services/TranslationPlatformServiceV1.cs
+++ b/src/Serval/src/Serval.Translation/Services/TranslationPlatformServiceV1.cs
@@ -270,22 +270,14 @@ public override async Task<Empty> UpdateBuildExecutionData(
         ServerCallContext context
     )
     {
-        var build = await _builds.GetAsync(request.BuildId, cancellationToken: context.CancellationToken);
-        if (build == null)
-        {
-            throw new RpcException(new Status(StatusCode.NotFound, "Build not found."));
-        }
-
-        var updatedExecutionData = new Dictionary<string, string>(build.ExecutionData);
-
-        foreach (var entry in request.ExecutionData)
-        {
-            updatedExecutionData[entry.Key] = entry.Value;
-        }
-
         await _builds.UpdateAsync(
             b => b.Id == request.BuildId,
-            u => u.Set(b => b.ExecutionData, updatedExecutionData),
+            u =>
+            {
+                // initialize ExecutionData if it's null
+                foreach (KeyValuePair<string, string> entry in request.ExecutionData)
+                    u.Set(b => b.ExecutionData[entry.Key], entry.Value);
+            },
             cancellationToken: context.CancellationToken
         );