Yup, looks like somebody installed non-hardened pushrods and they're all getting chewed up.
If it were my engine, I'd pull the intake and visually inspect the lifter and the cam lobe. It should be fine, but better safe than sorry. If you find the lifter laying in the valley, you may have issues with the bearings due to loss of
oil pressure.
For what it's worth, I had a customer who bought a shortblock from me use pushrods from a well respected manufacturer that were supposed to be hardened, and they all got chewed up like yours inside thirty minutes.