Have you tried allowing the hourglass to spin of at least 30-60 seconds...to see if the double rewards appear?
I find that it sometimes happens to me & I just let the hourglass spin & it seems to make the double rewards appear most times....but there are still sometimes that it doesn't work.
One of the tricks that I do is that just before I finish a quest or clear a game scene or claim an achievement is that I shut my game app down & then restart it.
Myself & other players have also found that if you have been playing for about an hour then it's best if you also shut down & then restart to have less issues with the double rewards.
I have also noticed that if I have multiple apps open or if I'm on a phone call that the double rewards ads don't work most of the time either....so I have to close all my apps & not be on a phone call.
Clearing cache, cookies, history, etc regularly seems to also be of some assistance as well.
I have found that I don't seem to have as many issues with the double rewards failing as much when I do these things.
Have you gone through the usual fault finding techniques?
First & foremost...write down your player ID number BEFORE you do anything....it can be found in the settings area of your game.
Are you running the most up-to-date version of the game app?
Have you tried uninstalling & re-installing the game app (but only do this if you have your game progress & player ID registered with either your email address or Facebook account)?
Have you tried turning off/closing down all other applications that are running on your phone?
Have you tried the other usual things such as:
- Logging out & in of game app/browser/Facebook/portal/Google Play
- Switching device off & on?
- Switching internet source/connection off & on
- Using a different source of internet (WiFi vs mobile data)?
- Using a different browser?
- Using different device/PC?
Have you tried playing through the portal/Facebook instead of through the mobile app or vice versa?
If none of these suggestions work you may need to contact Pixel support directly.... remember to check your spam folder....do NOT send in multiple support tickets in quick succession otherwise Pixels spambot may eat them.