As opposed to the others replying here, mine was a different experience.

These pics show cap-walk in a 360 SB (non-stroker) street engine. Nothing crazy here - stock crank with HP116CP pistons - other than all using ARP fasteners and the block having been machined correctly to true everything up. That was a flat tappet hydraulic cam with high-rev lifters, I regularly spun to 6500 RPM.

So did this cause any damage?

I do not think so, the crank came out looking very nice, no scoring on the journals, although the bearings did show a little wear and those locations coincided with where the cap-walk witness marks showed up.

Because of this I went to main studs on my W2 stroker build. The assembly difference was a 'day & night' kind of a thing: for the lack of better terms, the bottom end - as I was torquing down the studs - literally felt like a SOLID piece of iron! lol