Prevent webhook loops

app/models/qbo_invoice.rb

@@ -115,6 +115,10 @@ class QboInvoice < ActiveRecord::Base
       # TODO create hook for seperate plugin 
       begin
         if cf.name.eql? "VIN"
+          # Only update if blank to prevent infite loops
+          # TODO check cf_sync_confict flag once implemented
+          if cf.string_value.to_s.blank?
+
             vin = Vehicle.find(issue.vehicles_id).vin
             break if vin.nil?
             if not cf.string_value.to_s.eql? vin
@@ -122,6 +126,8 @@ class QboInvoice < ActiveRecord::Base
               logger.debug "VIN has changed"
               is_changed = true
             end
+
+          end
         end
       rescue
         #do nothing