Odd Suspension Issue "Fixed" Itself

Hi folks, hoping someone can shed some light on this and/or has maybe even experienced it...

First a little background: Car is a '73 Dart Custom 4-door beat-up daily driver my wife had when I met her and which she's driven daily since then, some 30 years. All stock, recent (around 9 months) upper ball joints, tie-rod ends, idler arm, and front strut rod bushings, alignment & ride height to stock spec.

Issue: While at work I got a text from her saying the car was making a tire-squealing noise and driving funny when she left the local Costco parking lot, having been fine up to that point. So she took slow back roads home and left it for me.

At first look I could see the front suspension was jacked up so high I would have thought someone had stolen the engine had she not driven it home. The driver-side wheel was also noticeably positive-cambered and toed-in (hence the squealing). My fellow gear-head neighbor said he'd never seen a suspension look like that outside of the drag strip following an unplanned wheel stand (and that was coil springs coming out of their anchors, so not the answer here).

I jacked it from the center crossmember to get both wheels off the ground & proceeded to start looking for what was broken or loose, which was nothing. Ran the steering lock-to-lock and didn't hear/feel/see anything weird, so proceeded to jack each side separately from the lower control arms, at which time I discovered the lower ball joints are pretty loose both axially & radially.

So I set the thing back down & told the wife I'd have to order some parts, backed it out of the driveway onto the street, and saw a puzzled look on my neighbor's face as I parked next to the curb and he (and I, upon getting a look) realized the suspension had returned to normal.

I already know it needs lower ball joints, but I don't like problems that seem to resolve themselves followed by parts-shotgunning in hopes it doesn't happen again.

Question: Any theories or experience as to what was going on here?

Thanks for reading, Mark