What you might consider is leaving the last gallon of sparge on the mash for an extra 15 minutes or so. Also, rake the surface of the mash during the sparge to reduce channeling.
Remember one unassailable statistic, as explained by the late, great George Carlin: "Just think of how stupid the average person is, and then realize half of them are even stupider!"
"I would like to die on Mars, just not on impact." Elon Musk