hasChanged detecting further back than expected

Using hasChanged command is causing a transition when I do not expect it to. This model is running discretely with a dt=0.01. The input (Apple) is a sin wave with a magnitude of 2 and a freq of 1.

trans 1 is being taken 1 dt after trans 2 but the value of b is the same as it was at the end of the last dt.

Windows 7 Matlab 2012b 32bit