Sharepoint SPFx Application Customiser

Question

My first attempt at building SharePoint application customiser. This is to modify the favicon on a particular site. When I gulp --serve the app works as expected, however when I: gulp clean gulp bundle --ship gulp package-solution --ship And upload to app catalogue, then add to my site. I get this error below, I can't seem to find the mentioned unterminated string, forgive my question, maybe I'm missing something obvious, but this is all new to me so any assistance or being pointed in the correct direction would be much appreciated.

The content database on the server is temporarily unavailable.Details: Deployment failed in host web https://lsvic.sharepoint.com/sites/Compass for app sp-favicon-client-side-solution/8f83ac8d-d058-4dd8-8c05-e4deb832636b. System.Exception: HandleProvisioningException
 rethrowing: The specified value for property ClientSideComponentProperties is not a valid JSON string, exception: Newtonsoft.Json.JsonReaderException: Unterminated string. Expected delimiter: ". Path 'faviconpath', line 1, position 82. at Newtonsoft.Json.JsonTextReader.ReadStringIntoBuffer(Char
 quote) at Newtonsoft.Json.JsonTextReader.ParseString(Char quote) at Newtonsoft.Json.JsonTextReader.ParseValue() at Newtonsoft.Json.JsonTextReader.Read() at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateJObject(JsonReader reader) at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(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 Microsoft.SharePoint.SPUserCustomAction.ValidateClientSideAction().
 ---> Microsoft.SharePoint.SPException: The specified value for property ClientSideComponentProperties is not a valid JSON string, exception: Newtonsoft.Json.JsonReaderException: Unterminated string. Expected delimiter: ". Path 'faviconpath', line 1, position
 82. at Newtonsoft.Json.JsonTextReader.ReadStringIntoBuffer(Char quote) at Newtonsoft.Json.JsonTextReader.ParseString(Char quote) at Newtonsoft.Json.JsonTextReader.ParseValue() at Newtonsoft.Json.JsonTextReader.Read() at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateJObject(JsonReader
 reader) at Newtonsoft.Json.Serialization.JsonSerializerInternalReader.CreateObject(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 Microsoft.SharePoint.SPUserCustomAction.ValidateClientSideAction(). at Microsoft.SharePoint.Utilities.SPUtility.ThrowSPExceptionWithTraceTag(UInt32 tagId, ULSCat traceCategory, String resourceId, Object[]
 resourceArgs) at Microsoft.SharePoint.SPUserCustomAction.ValidateClientSideAction() at Microsoft.SharePoint.SPUserCustomAction.Update() at Microsoft.SharePoint.SPWebUserCustomAction.Update() at Microsoft.SharePoint.SPCustomActionElement.AddCustomActionToDatabase(SPSite
 site, SPWeb webNull) at Microsoft.SharePoint.SPCustomActionElement.UpdateCustomActionsTable(SPFeature feature, SPSite site, SPWeb web, CultureInfo cultureInfo, Boolean fForce) --- End of inner exception stack trace --- at Microsoft.SharePoint.SPFeature.HandleProvisioningException(Exception
 e, Boolean force) at Microsoft.SharePoint.SPCustomActionElement.UpdateCustomActionsTable(SPFeature feature, SPSite site, SPWeb web, CultureInfo cultureInfo, Boolean fForce) at Microsoft.SharePoint.SPFeature.UpdateCachedFeatureDefinitionInformation(SPSite site,
 SPWeb web, Boolean fForce) at Microsoft.SharePoint.SPFeature.Activate(SPSite siteParent, SPWeb webParent, SPFeaturePropertyCollection props, SPFeatureActivateFlags activateFlags, Boolean fForce) at Microsoft.SharePoint.SPFeatureCollection.AddInternal(SPFeatureDefinition
 featdef, Version version, SPFeaturePropertyCollection properties, SPFeatureActivateFlags activateFlags, Boolean force, Boolean fMarkOnly) at Microsoft.SharePoint.Packaging.SPTargetWebDeploymentGroup.InstallOrUpgrade(SPSite site, Nullable``1& solutionId, Boolean&
 swapNeeded)