I did a contact Delta today.
Same thing happened to me.
The 2010 miles posted for one of my stays and then deleted and replaced with a 1005 for one of the stays. Nothing for the others.

The ? is this a DL issue or a Hilton issue.

Here is what the promo said:

HHONORS Delta 2010 3 night stay
Where will 2,010 bonus miles take you?
Terms & Conditions: To be eligible for this offer, you must (1) be both a member of Hilton HHonors® and Delta SkyMiles reward programs; (2) select Delta SkyMiles as your Double Dip earnings partner in your Hilton HHonors Profile Account; (3) register at. http://www.hiltonhhonors.com/DeltaQ4promo. before your check-in for your stay; and (4) complete a minimum three-night stay at a participating Hilton Worldwide hotel from November 15, 2009 through February 28, 2010. You must be a Hilton HHonors member to earn Points & Miles for hotel stays. To view participating hotels, please click here. Bonus Delta Mileage:. Earn 2,010 bonus miles in the Delta SkyMiles program, in addition to base HHonors points and miles for each qualifying three-night stay at participating hotels. A maximum bonus of 2,010 bonus miles to be awarded per stay, regardless of the number of rooms/nights booked exceeding offer minimum. Bonus miles are not eligible to earn EQMs. Please allow up to six weeks after the promotion has ended for bonus miles to be credited to your SkyMiles® account..
All SkyMiles program rules apply. To review the rules, please visit delta.com/skymiles.. Certain negotiated and group rates are ineligible for participation, for a full listing of excluded rates, please click here.. Reward stays are not eligible for this offer. Other restrictions may apply. Hilton HHonors membership, earning of Points & Miles and redemption of points are subject to HHonors Terms and Conditions. © 2009 Hilton Worldwide. All rights reserved.