[Environment:] Windows 10, OSX 10.12 56.0b12 20170914024831 [Preconditions:] You need access to Admin interface (https://normandy-admin.stage.mozaws.net/control) or New Admin interface (https://normandy-admin.stage.mozaws.net/control-new) 1. Obtain a copy of Firefox with the SHIELD recipe client system add-on installed. You can check about:support to ensure that you have it. 2. Set the extensions.shield-recipe-client.dev_mode preference to true to run recipes immediately on startup. 3. Set the extensions.shield-recipe-client.logging.level preference to 0 to enable more logging. 4. Set the security.content.signature.root_hash preference to DB:74:CE:58:E4:F9:D0:9E:E0:42:36:BE:6C:C5:C4:F6:6A:E7:74:7D:C0:21:42:7A:03:BC:2F:57:0C:8B:9B:90. 5. Set the preference value for extensions.shield-recipe-client.api_url set to https://normandy.stage.mozaws.net/api/v1 [Steps:] 1. Open Firefox with new profile. 2. Set the preconditions. 2. Open about:studies page. 3. Restart Firefox. [Actual Result:] The auto session restore will kick in and will show the about:studies page, but the page would be in a "The address isn’t valid" state. Refreshing the page will show the right content.

I think this is the browser console relevant for this issue: Given tab is not restoring. SessionStore.jsm:4697 _resetLocalTabRestoringState resource:///modules/sessionstore/SessionStore.jsm:4697:7 receiveMessage resource:///modules/sessionstore/SessionStore.jsm:973:9