Okay, I'll throw my hat in this thread ...  2,4-D has been known to injure wheat for decades now.  The question is at what rate.  2,4D LV4 or LV6 is used on many acres in Kentucky, but not for weed control as much as a "safener" for Harmony.  Harmony was the first effective herbicide for wild garlic control, but when sprayed alone, it will shorten wheat heads.  Adding low rates of 4-8 fl. oz. of 2,4-D LV4 (4-6 ounces LV6) will safen the Harmony.  At these rates wheat injury is avoided.  There's plenty of data from university and consultants to show that 1-2 pints of 2,4-D will injure wheat, but no problems with the lower rates.

I have gone to fall applications of herbicides in wheat with terrific results, especially for Italian ryegrass so I rarely spray in the spring, but if I did, I would definitely add 2,4-D at 4-6 ounces (LV6) to the mix if Harmony is used.  Quelex is the primary spring herbicide used in our area because of the weed resistance to group 2 herbicides for weeds like chickweed.