Could it be that there are minor differences in the thickness/ harness of the brass at the rim? Revolver hammers generally don't have the force of a rifle striker. I had a 22 WRF (same basic case) Taurus revolver that had misfires with Aguila ammo until it had 200 rounds run through it, It works fine now. Could be part-gun, part-ammo issue.
Ammo age is an unlikely factor with any kind of reasonable storage for Post WW2 ammo. I have some GI ( probably Winchester production)22 LR ammo from 1952 that fires to exact specified velocity.
The general rule is that commercial ammo stopped using Mercuric primers about 1940 and U.S.military centerfire ammo stopped in 1952 with two exceptions: 30 Carbine never had mercuric primers and 30-06 match ammo used mercuric primers into the late 1960's. Really old mercuric primed ammo should not be fired because the mercury can make the brass brittle over time which could result in a case head rupture. ( had this happen with a round of GI 30-06 dated 1923)