Hydr lifters, adjustable roller rocker arms, had some noise, tried to adjust preload did i mess up?

One other thought.......

If the motor had been revved to the point where there was noticeable valvetrain instability, and the pushrods were dancing around a little......... I’ve seen it where the bottom of the pushrod will “step on” the plunger retaining clip and dislodge and/or deform it.
I’ve seen it happen several times with fast rate cams and lifters that are simply unable to keep up.

Looking down past the head into the valley(easier on some heads than others), careful inspection of the tops of the lifters should reveal if that situation is an issue or not.