Not a bug this is Gi goal want players spend real money and this event when it start is the hardest event and nothing change the same every time.GI wants players to spend all the greenies accumulated by us collecting them from the cars of the Christmas events, I guess this is also the reason for them to stop giving new bonus codes, and introducing continuous sale for greenies.
I don't know if it is a bug or what but got the 3x greenies sale continuously for almost 4 weeks and only 1 expansion sale
Some can spend real money and other cannot but they keep playing for other destination.