This is a bizarre one!
I signed up for my targeted DL One Bite At A Time bonus when it came out, but waited until the (extended) UA bonus from earlier this year had finally ended (at the end of May). So I started dining with DL at the start of June.
Then I got the targeted AA 10,000 Reasons To Party bonus, and shifted to that in August.
It's now mid-August, and I get the following email from DL (SkyMiles Dining):
Hope you're hungry, because the feast starts now
We're ready to serve you... double
Dine for twice the miles
Wherever you've been eating lately, it hasn't been at SkyMiles(R) Dining restaurants. That means you're missing out on miles.
Now is the perfect time to come back to the table, because you'll automatically earn double miles on every dine through the end of the month. (See below for details.)
You don't need to register—just dine!
*This bonus offer is by invitation only for select existing SkyMiles Dining members. To qualify, you must remain opted in to receive emails from SkyMiles Dining with a valid, deliverable email address.
To earn double rewards through this bonus, you must dine at participating restaurants, bars or clubs between August 15 and August 31, 2012. Please note that activity that occurred prior to registration will not be eligible for this bonus. In addition, all dines must occur during a valid reward period and be paid for with a credit or debit card registered with SkyMiles Dining. You may earn this bonus multiple times. Offer is not combinable with other SkyMiles Dining bonuses. Please allow 4–6 weeks from the date of your qualifying dine for any bonus benefits to post to your SkyMiles Dining account. All account inquiries related to this bonus must be received by December 31, 2012.
By the way, after a lengthy call to RN CS, I was informed that the email is incorrect about the "not combinable". They said that since one bonus (One Bite At A Time) was registered for, but this bonus (whatever it's called!) does not require registration, they can and do "stack".
However, note the other discrepancy: The email was sent today, August 13, and it says to dine "now". But a dine today or tomorrow won't earn double. The fine print says that the bonus starts August 15, and RN CS confirmed that part is correct. (And thus the "now" part is incorrect!)