If you mean by 'de-priming' that that lifter starts to leak off, it does not seem like it should do that. The rocker may be able to put more pressure on the lifter when it is cocked, than you can by hand. But it won't hurt to replace that one rocker and see. It'll be interesting to see the shaft surface under that rocker.
You do know you can pull the lifters out with the stock heads with the right tool?
