To T12 - essentially the inner core has been spnning around, inside of the outer eyewall, like a ball inside of the rim of a hola hoop, giving a wobbly appearance, but actually is a predictable movement. Now that the center over time has gotten mashed up so to speak, the effect of the oscillation on the storm as a whole was reduced and movement outside of the large eyewall was minimized, but movement inside of it was still oscillating, while over landfall since early this morning. Tpratch's diagram shows the movement a bit when it was approaching the Yucatan (it looks like a series of curves like a bouncing ball). However now as the inner core becomes more disorganzied, even that will become less discernable, and once over water, the larger eyewall will eventually clear out and the radius will decrease.

This is generally only a feature of stronger storms and especially in cases of lopsided circulation.