diff --git a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipDriver.cs b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipDriver.cs
index f621240d..a80a86e0 100644
--- a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipDriver.cs
+++ b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.AbCip/AbCipDriver.cs
@@ -106,10 +106,10 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
     private readonly Dictionary<string, DeviceState> _devicesByRoutingKey = new(StringComparer.OrdinalIgnoreCase);
     // v3 authored RawPath → definition table (parents + fanned-out UDT members), keyed case-sensitive
     // ordinal. Built in InitializeAsync from _options.RawTags via the pure mapper.
-    private readonly Dictionary<string, AbCipTagDefinition> _tagsByRawPath = new(StringComparer.Ordinal);
+    private volatile Dictionary<string, AbCipTagDefinition> _tagsByRawPath = new(StringComparer.Ordinal);
     // Top-level authored definitions (parents + flat tags, NOT synthesised members), in author order —
     // the source DiscoverAsync groups by device. Members are synthesised inside the discovery/read paths.
-    private readonly List<AbCipTagDefinition> _declaredTags = new();
+    private volatile List<AbCipTagDefinition> _declaredTags = new();
 
     // Resolves a read/write/subscribe fullReference (always a RawPath in v3) to a tag definition by a
     // single hit on the authored _tagsByRawPath table; a miss is a miss (the pre-v3 blob-parse fallback
@@ -377,6 +377,8 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
             // threaded onto the def (they live on the RawTagEntry, not inside the blob). A mapper miss is
             // skipped (logged), never thrown — a bad tag must not fail the whole driver init.
             _skippedTags.BeginRebuild(_options.RawTags.Count);
+            var builtTagsByRawPath = new Dictionary<string, AbCipTagDefinition>(StringComparer.Ordinal);
+            var builtDeclaredTags = new List<AbCipTagDefinition>();
             foreach (var entry in _options.RawTags)
             {
                 if (!AbCipTagDefinitionFactory.FromTagConfig(entry.TagConfig, entry.RawPath, out var mapped))
@@ -391,13 +393,13 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
 
                 // Duplicate-key check: a collision means two authored tags share the same RawPath.
                 // Fail fast at init time with a diagnostic rather than silently clobbering.
-                if (_tagsByRawPath.TryGetValue(tag.Name, out var existingTag))
+                if (builtTagsByRawPath.TryGetValue(tag.Name, out var existingTag))
                     throw new InvalidOperationException(
                         $"AbCip tag name collision: '{tag.Name}' is declared more than once. " +
                         $"Existing entry DeviceHostAddress='{existingTag.DeviceHostAddress}', " +
                         $"TagPath='{existingTag.TagPath}'. Rename or remove the duplicate.");
-                _tagsByRawPath[tag.Name] = tag;
-                _declaredTags.Add(tag);
+                builtTagsByRawPath[tag.Name] = tag;
+                builtDeclaredTags.Add(tag);
 
                 if (tag.DataType == AbCipDataType.Structure && tag.Members is { Count: > 0 })
                 {
@@ -420,15 +422,18 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
                         // Member fan-out duplicate check: a member-path collision means two
                         // configured structure tags produce the same member path, or a member
                         // name collides with an independently-declared tag.
-                        if (_tagsByRawPath.TryGetValue(memberTag.Name, out var existingMember))
+                        if (builtTagsByRawPath.TryGetValue(memberTag.Name, out var existingMember))
                             throw new InvalidOperationException(
                                 $"AbCip tag name collision: '{memberTag.Name}' is produced by both " +
                                 $"'{tag.Name}.{member.Name}' (member fan-out) and an existing tag " +
                                 $"'{existingMember.Name}'. Rename one of the configured tags to resolve.");
-                        _tagsByRawPath[memberTag.Name] = memberTag;
+                        builtTagsByRawPath[memberTag.Name] = memberTag;
                     }
                 }
             }
+            // Publish the finished tables by reference swap — readers see the old or the new, never a half-built one.
+            _tagsByRawPath = builtTagsByRawPath;
+            _declaredTags = builtDeclaredTags;
             _skippedTags.Commit();
 
             // Probe loops — one per device when enabled + a ProbeTagPath is configured.
@@ -498,8 +503,8 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
         _devices.Clear();
         _devicesByRoutingKey.Clear();
         // Rebuilt wholesale by Initialize; stale entries would trip its member fan-out collision check.
-        _tagsByRawPath.Clear();
-        _declaredTags.Clear();
+        _tagsByRawPath = new(StringComparer.Ordinal); // swap, never Clear(): the retained poll engine / discovery may be enumerating
+        _declaredTags = new();
     }
 
     /// <inheritdoc />
@@ -546,8 +551,8 @@ public sealed class AbCipDriver : IDriver, IReadable, IWritable, ITagDiscovery,
         }
         _devices.Clear();
         _devicesByRoutingKey.Clear();
-        _tagsByRawPath.Clear();
-        _declaredTags.Clear();
+        _tagsByRawPath = new(StringComparer.Ordinal);
+        _declaredTags = new();
         _resolver.Clear(); // no-op in v3 (the resolver reads the live table by closure); kept for symmetry
         _health = new DriverHealth(DriverState.Unknown, _health.LastSuccessfulRead, null);
     }
diff --git a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.S7/S7Driver.cs b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.S7/S7Driver.cs
index adda1429..9ae9c4d6 100644
--- a/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.S7/S7Driver.cs
+++ b/src/Drivers/ZB.MOM.WW.OtOpcUa.Driver.S7/S7Driver.cs
@@ -400,6 +400,10 @@ public sealed class S7Driver
         // teardown, in which case we proceed exactly as the un-gated path always did.
         var gated = false;
         try { gated = await _gate.WaitAsync(DrainTimeout).ConfigureAwait(false); } catch { }
+        if (!gated)
+            _logger.LogWarning(
+                "S7 driver {DriverInstanceId}: disposing the S7 connection while an operation still holds the gate (waited {Timeout})",
+                _driverInstanceId, DrainTimeout);
         try
         {
             _initialized = false;