your available water is insanely low, is that an accurate number, i mean, that getting pretty close to concrete.
with such a low number i would expect this behavior.
5 inches of root zone * .05 of awc = .25 inches of water, you allowed depletion is 50% so
.25 * .50 = .125 inches, round up to nearesth 100th and that is why you are getting an irrigation event of .13 inches of water.
to me, things look correct, if, the precipitation event that occurred on the 26th, occurred at midnight of the 26th.