So, here's the theory - not my theory - take it for what you will.
The staff always wanted Lenhart more, with Williams the other option for the second EDGE with Noonan. Word is Williams tried to commit to Minnesota but they told him they didn't have a spot for him. So he rushed his commitment announcement to Nebraska without getting the go-ahead from the coaches. Which is why there weren't any Twitter reactions from the staff.
Presumably, we told him we're waiting to hear from Lenhart first so he flipped his commitment to Auburn.