fix: create fresh objects for all default header scopes

lib/plugin.template.js

@@ -114,16 +114,31 @@ const baseURL = process.browser
 export default (ctx) => {
   const { app, store, req } = ctx
 
+  // Create a fresh objects for all default header scopes
+  // Axios creates only one which is shared across SSR requests!
+  // https://github.com/mzabriskie/axios/blob/master/lib/defaults.js
+  const headers = {
+    common : {
+      'Accept': 'application/json, text/plain, */*'
+    },
+    delete: {},
+    get: {},
+    head: {},
+    post: {},
+    put: {},
+    patch: {}
+  }
+
   <% if(options.proxyHeaders) { %>
   // Default headers
-  const defaultHeaders = (req && req.headers) ? Object.assign({}, req.headers) : {}
-  delete defaultHeaders.host
+  headers.common = (req && req.headers) ? Object.assign({}, req.headers) : {}
+  delete headers.common.host
   <% } %>
 
   // Create new axios instance
   const axios = Axios.create({
     baseURL,
-    <% if(options.proxyHeaders) { %>headers: { common: defaultHeaders },<% } %>
+    headers
   })
 
   <% if(options.credentials) { %>