diff --git a/src/common/auth/fetch_token.js b/src/common/auth/fetch_token.js
index ac0033755a..e96153127b 100644
--- a/src/common/auth/fetch_token.js
+++ b/src/common/auth/fetch_token.js
@@ -9,8 +9,9 @@ export default function fetchToken(clientId, code) {
     body: data,
   }).then((resp) => {
     if (!resp.ok) throw new Error('Unable to fetch tokens');
-    const tokens = resp.json();
-    tokens.expires = (tokens.expires_in * 1000) + Date.now();
-    return tokens;
+    return resp.json().then((tokens) => {
+      tokens.expires = (tokens.expires_in * 1000) + Date.now();
+      return tokens;
+    });
   });
 }
diff --git a/src/common/auth/refresh_token.js b/src/common/auth/refresh_token.js
index 30df3ebfa5..2a11aa1e64 100644
--- a/src/common/auth/refresh_token.js
+++ b/src/common/auth/refresh_token.js
@@ -9,8 +9,9 @@ export default function refreshAccessToken(clientId, refreshToken) {
     body: data,
   }).then((resp) => {
     if (!resp.ok) throw new Error('Unable to fetch tokens');
-    const tokens = resp.json();
-    tokens.expires = (tokens.expires_in * 1000) + Date.now();
-    return tokens;
+    return resp.json().then((tokens) => {
+      tokens.expires = (tokens.expires_in * 1000) + Date.now();
+      return tokens;
+    });
   });
 }
diff --git a/src/entrypoints/core.js b/src/entrypoints/core.js
index 0de0d6ce7a..2c1adfbf40 100644
--- a/src/entrypoints/core.js
+++ b/src/entrypoints/core.js
@@ -39,7 +39,7 @@ function redirectLogin() {
 
 window.refreshToken = () =>
   refreshToken_(clientId(), window.tokens.refresh_token).then((accessTokenResp) => {
-    window.tokens.access_token = accessTokenResp.access_token;
+    window.tokens = Object.assign({}, window.tokens, accessTokenResp);
     localStorage.tokens = JSON.stringify(window.tokens);
     return {
       access_token: accessTokenResp.access_token,