I think I've identified the problem to the float of the Look Keo cleats I just installed on my new Lake Cycling TX312 tri-shoes. There should be 4.5-degrees of float with the gray cleats. I initially thought that I'd misaligned the cleats so I put my old shoes on my bike and check the distance from the center of the heal to my crank. I did the same with my new shoes for comparison. That's when I noticed that, although the cleats were the same model, the new cleats only moved with some force applied.
It's possible that the float issue will correct itself with more use. I'm glad that I noticed this problem well before Ironman Florida.
Thanks for reading.