Logged in just now, and my daily reward progression for September has been reset. This has occurred identically on two accounts. I was approx. 12 days in (I believe I missed a day earlier in the month), but just now collected the day 1 reward again, for the second time.
As things currently stand, getting to the 100K gold at the end of the month is now impossible.
There is really not much use in having any sort of "progression" in this rewards system if things like this are going to happen. Perhaps you should just give us a random daily reward, and we can relax and just log in if/when we get a chance.