I went through this with AFR on my 468 several years back. They use what are thought of as high end springs from PAC. I broke 9 inner springs (not dampers but an actual inner spring). Worked fine on the dyno and about 2,000 street miles.
Ironically my engine still ran fine, I had pulled the covers for another reason and found that
The explanation I got from AFR (and I'm sure they were trying to cover their butts) was that there was a bad batch of springs floating around the market that others also had issues with, and it had since been addressed.
I've also heard of this happening in recent months with other springs. Seems every so often cylinder head manufactures want to blame a bad batch of springs hitting the market.
I don't know how much truth there is to that, but I feel your pain. There is that worry that some smaller pieces could have made it down the drain holes and into the oil system (unless you epoxy some screens at the drains, I do that on all the engines I build).
With that small cam you have, a single spring with damper is enough spring pressure. You'll have to check the valve guide bosses if it has chewed up your seals, it could beat the tops of the guides too (it did on mine).
Hopefully it's not too bad and a new set of springs and seals will get you back up and running.