SB Crane Retrofit Roller Lifter Issue

I hooked up a mechanical gauge and oil pressure is around 77-79 PSI during that test. If I put that leaky lifter at max lift and jiggle it around, which makes it leak more, then the gauge reads a steady 75 psi. If I pull a lifter completely out of the driver's side then I get 45 psi of oil pressure. If I pull a lifter completely out on the passenger's side I get 0 pressure. But all the lifters on the passenger's side are nice and deep in their bores, no issues over there. The lifter in question is on the driver's side.