It's possible the lifter is worn/mushroomed enough on the bottom to make it difficult to remove. If so, both cam and lifters should be replaced. A good lifter will have a slight convex shape on the bottom where it rides the cam, taller in the middle than the edges. This, plus the lifter riding slightly off-center on the cam lobe causes it to spin as it lifts, equalizing the wear pattern. Flat-bottomed or cupped-out lifters are worn out. Check the bottoms with a straightedge like a machinist's 6-inch rule.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
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