So I made some poor decisions lately in spending my gold, and decided to roll back to my cloud saved game to undo the damage. Unfortunately, I hadn't realized that my most recent saved game was one from just after the Ferrari update - about a month ago. Bit that was OK - I knew I mostly would have to re-do all of the Time Trials, plus re-race the Ferrari series and a couple more. No big deal - I could restock some gold from re-racing the TTs and get back to where I was.
Well, I've been re-racing the Time Trials to get back to 100% for each series and behold - I am NOT getting the 2 Gold anymore (nor the R$) for completing the series! For some reason the cloud roll-back did not re-set the completion of each the series, and the game must think I've already completed them. That's around 70 Gold I cannot recover - ouch!!
Lesson here is an oldie - cloud save often. But also be aware that once you've re-completed the TTs for your 2 gold each, going back may not undo those completions, even though of course going back takes away any gold and money you had earned.