How do hydraulic flat tappet lifters fail?

I'm suspect of a lot of modern speed part quality. In the 80's and 90's if you wiped a lobe on a performance cam it was usually installer and break in error. But they were much more forgiving.
I watched a comp cam and lifters eat themselves in a 383 with flawless break in. I didn't assemble it so I can't say all assembly was perfect but it was a well respected professional.

Other than proper break in the only extra precautions we took, back when I was building these things,was to run a small ball hone in the lifter bores and round any sharp edges.
I recall new lifters would sometimes mic very slightly fatter that used ones. I also figured the pattern the hone would put in the bored would encourage lifter rotation.

The last time I mentioned that to the internet hive mind I was told how wrong that procedure was and I'm so stupid it's a miracle I can breathe.

But I've never lost a cam in anything I ever built doing this. But your mileage may vary.