It could be a problem with the model. As the comment in the code says, DataTypes of Boolean, String and Byte should not be defined as a concurrency column.
If the field in question is meant to be a concurrency property, please make sure that it is not one of those data types.
If it was not meant to be a concurrency property, perhaps you can post a code snippet on how you're defining your model.
EDIT:
If, for any reason, that you're unable to change the model, you can bypass Breeze's concurrency check by implementing this hack:
entityManager.metadataStore.getEntityTypes()
.forEach(function(entityType) {
entityType.concurrencyProperties = [];
});
Please note that with this implementation, you are now responsible for having your own concurrency check mechanism, either on the client or on the server.