NServiceBus - Could not load file or assembly '' or one of its dependencies

I am working with an .Net Web App that consumes messages from a NServiceBus (v4.7.0) queue. I am getting the following exception:

2019-02-20 15:35:13,624 [28] ERROR NServiceBus.Unicast.Transport.TransportReceiver [(null)] - [(null)] - Failed to deserialize message with ID: 0942d9eb-126e-4af6-b860-a9f400a3be82 System.Runtime.Serialization.SerializationException: An error occurred while attempting to extract logical messages from transport message NServiceBus.TransportMessage ---> System.IO.FileLoadException: Could not load file or assembly 'xpto.Contracts, Version=1.0.0.0, Culture=neutral, PublicKeyToken=6a17a7d57c13b3cf' or one of its dependencies. The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040) ---> System.IO.FileLoadException: The located assembly's manifest definition does not match the assembly reference. (Exception from HRESULT: 0x80131040) --- End of inner exception stack trace ---
at System.RuntimeTypeHandle.GetTypeByName(String name, Boolean throwOnError, Boolean ignoreCase, Boolean reflectionOnly, StackCrawlMarkHandle stackMark, IntPtr pPrivHostBinder, Boolean loadTypeFromPartialName, ObjectHandleOnStack type) at System.RuntimeTypeHandle.GetTypeByName(String name, Boolean throwOnError, Boolean ignoreCase, Boolean reflectionOnly, StackCrawlMark& stackMark, IntPtr pPrivHostBinder, Boolean loadTypeFromPartialName) at System.RuntimeType.GetType(String typeName, Boolean throwOnError, Boolean ignoreCase, Boolean reflectionOnly, StackCrawlMark& stackMark) at System.Type.GetType(String typeName, Boolean throwOnError) at NServiceBus.Unicast.Messages.MessageMetadataRegistry.GetMessageMetadata(String messageTypeIdentifier) in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Unicast\Messages\MessageMetadataRegistry.cs:line 52 at NServiceBus.Unicast.Messages.ExtractLogicalMessagesBehavior.Extract(TransportMessage physicalMessage) in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Unicast\Messages\ExtractLogicalMessagesBehavior.cs:line 75 at NServiceBus.Unicast.Messages.ExtractLogicalMessagesBehavior.Invoke(ReceivePhysicalMessageContext context, Action next) in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Unicast\Messages\ExtractLogicalMessagesBehavior.cs:line 52 --- End of inner exception stack trace --- at NServiceBus.Unicast.Messages.ExtractLogicalMessagesBehavior.Invoke(ReceivePhysicalMessageContext context, Action next) in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Unicast\Messages\ExtractLogicalMessagesBehavior.cs:line 56 at NServiceBus.Pipeline.BehaviorChain1.Invoke() in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Pipeline\BehaviorChain.cs:line 35 at NServiceBus.Sagas.RemoveIncomingHeadersBehavior.Invoke(ReceivePhysicalMessageContext context, Action next) in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Sagas\RemoveIncomingHeadersBehavior.cs:line 23 at NServiceBus.Pipeline.BehaviorChain1.Invoke() in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Pipeline\BehaviorChain.cs:line 35 at NServiceBus.Unicast.Behaviors.RaiseMessageReceivedBehavior.Invoke(ReceivePhysicalMessageContext context, Action next) in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Unicast\Behaviors\RaiseMessageReceivedBehavior.cs:line 18 at NServiceBus.Pipeline.BehaviorChain1.Invoke() in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Pipeline\BehaviorChain.cs:line 35 at NServiceBus.MessageMutator.ApplyIncomingTransportMessageMutatorsBehavior.Invoke(ReceivePhysicalMessageContext context, Action next) in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\MessageMutator\ApplyIncomingTransportMessageMutatorsBehavior.cs:line 22 at NServiceBus.Pipeline.BehaviorChain1.Invoke() in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Pipeline\BehaviorChain.cs:line 35 at NServiceBus.UnitOfWork.UnitOfWorkBehavior.Invoke(ReceivePhysicalMessageContext context, Action next) in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\UnitOfWork\UnitOfWorkBehavior.cs:line 34 at NServiceBus.Pipeline.BehaviorChain1.Invoke() in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Pipeline\BehaviorChain.cs:line 35 at NServiceBus.Unicast.Behaviors.ForwardBehavior.Invoke(ReceivePhysicalMessageContext context, Action next) in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Unicast\Behaviors\ForwardBehavior.cs:line 24 at NServiceBus.Pipeline.BehaviorChain1.Invoke() in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Pipeline\BehaviorChain.cs:line 35 at NServiceBus.Audit.AuditBehavior.Invoke(ReceivePhysicalMessageContext context, Action next) in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Audit\AuditBehavior.cs:line 17 at NServiceBus.Pipeline.BehaviorChain1.Invoke() in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Pipeline\BehaviorChain.cs:line 35 at NServiceBus.Unicast.Behaviors.ImpersonateSenderBehavior.Invoke(ReceivePhysicalMessageContext context, Action next) in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Unicast\Behaviors\ImpersonateSenderBehavior.cs:line 37 at NServiceBus.Pipeline.BehaviorChain1.Invoke() in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Pipeline\BehaviorChain.cs:line 35 at NServiceBus.Unicast.Behaviors.MessageHandlingLoggingBehavior.Invoke(ReceivePhysicalMessageContext context, Action next) in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Unicast\Behaviors\MessageHandlingLoggingBehavior.cs:line 21 at NServiceBus.Pipeline.BehaviorChain1.Invoke() in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Pipeline\BehaviorChain.cs:line 35 at NServiceBus.Unicast.Behaviors.ChildContainerBehavior.Invoke(ReceivePhysicalMessageContext context, Action next) in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Unicast\Behaviors\ChildContainerBehavior.cs:line 17 at NServiceBus.Pipeline.BehaviorChain1.Invoke() in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Pipeline\BehaviorChain.cs:line 35 at NServiceBus.Pipeline.PipelineExecutor.InvokeReceivePhysicalMessagePipeline() in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Pipeline\PipelineExecutor.cs:line 44 at NServiceBus.Unicast.UnicastBus.TransportMessageReceived(Object sender, TransportMessageReceivedEventArgs e) in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Unicast\UnicastBus.cs:line 1099 at NServiceBus.Unicast.Transport.TransportReceiver.OnTransportMessageReceived(TransportMessage msg) in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Unicast\Transport\TransportReceiver.cs:line 439 at NServiceBus.Unicast.Transport.TransportReceiver.ProcessMessage(TransportMessage message) in c:\BuildAgent\work\1b05a2fea6e4cd32\src\NServiceBus.Core\Unicast\Transport\TransportReceiver.cs:line 356

The funny thing is that I changed the "xpto.Contracts" signature and it no longer has the PublicKeyToken=6a17a7d57c13b3cf', can't find any reference to that key token. Where is this coming from?