Umbraco 7.3.0 / LG Starter Kit 5.1.2 : can't run site after loading example content. (No problems with LG Starter Kit 5.0.Beta1.)

Log Extract:

2015-11-23 11:38:30,616 [P3980/D25/T74] ERROR Umbraco.Web.PropertyEditors.ValueConverters.RelatedLinksEditorValueConvertor - Could not parse the string [ { "caption": "Starter Kit Help", "link": 8B40D7C0-E98E-49C7-BED3-B1DAFD92FAF7, "newWindow": false, "internal": 8B40D7C0-E98E-49C7-BED3-B1DAFD92FAF7, "edit": false, "isInternal": true, "internalName": "Help", "type": "internal", "title": "Starter Kit Help" }, { "caption": "Example Content", "link": 943E121F-ACFB-4C5F-BE60-1D0A5443E52D, "newWindow": false, "internal": 943E121F-ACFB-4C5F-BE60-1D0A5443E52D, "edit": false, "isInternal": true, "internalName": "Example", "type": "internal", "title": "Example Content" }, { "caption": "News", "link": 44E07320-C9B4-4426-B52F-0DB2430F53A9, "newWindow": false, "internal": 44E07320-C9B4-4426-B52F-0DB2430F53A9, "edit": false, "isInternal": true, "internalName": "News", "type": "internal", "title": "News" } ] to a json object Newtonsoft.Json.JsonReaderException: Input string '8B40D7C0-E98E-49C7-BED3-B1DAFD92FAF7' is not a valid number. Path '[0].link', line 4, position 49. at Newtonsoft.Json.JsonTextReader.ParseNumber() at Newtonsoft.Json.JsonTextReader.ParseValue() at Newtonsoft.Json.JsonTextReader.ReadInternal() at Newtonsoft.Json.JsonTextReader.Read() at Newtonsoft.Json.JsonWriter.WriteToken(JsonReader reader, Int32 initialDepth, Boolean writeChildren, Boolean writeDateConstructorAsDate) at Newtonsoft.Json.JsonWriter.WriteToken(JsonReader reader, Boolean writeChildren, Boolean writeDateConstructorAsDate) at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateJToken(JsonReader reader, JsonContract contract) at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateValueInternal(JsonReader reader, Type objectType, JsonContract contract, JsonProperty member, JsonContainerContract containerContract, JsonProperty containerMember, Object existingValue) at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.Deserialize(JsonReader reader, Type objectType, Boolean checkAdditionalContent) at Newtonsoft.Json.JsonSerializer.DeserializeInternal(JsonReader reader, Type objectType) at Newtonsoft.Json.JsonConvert.DeserializeObject(String value, Type type, JsonSerializerSettings settings) at Newtonsoft.Json.JsonConvert.DeserializeObject[T](String value, JsonSerializerSettings settings) at Umbraco.Web.PropertyEditors.ValueConverters.RelatedLinksEditorValueConvertor.ConvertDataToSource(PublishedPropertyType propertyType, Object source, Boolean preview)