I have not been able to reproduce the problem. After trying to reproduce the problem with critical duty ammo and my three hammer fired Ruger security nine compact pro pistols, I cleaned each one, loaded them with new critical duty ammo, and place them back in their staging areas. I’m now leaning toward Covid as the cause.
Well this has me curious about the two mags in my trunk loaded with HSTs for probably six months. They’re kept in an waterproof ammo box along with a spare box or two of everything I shoot for when I’m at the range and having more fun than I expected when I leave the house.
One thought I had about the OP’s problem, perhaps the firing pin or striker channel was somehow gummed up from being in the trunk. Most oils tend to evaporate over time and turn into goo or shellac. Doesn’t explain why the rounds from the house fired when the trunk stash didn’t unless firing somehow loosened up a sticky firing pin or striker.
Striker fired guns, by the way, should always be dry after cleaning, not oiled.