the new stone walls (limestone, marble, prismarine) seem to be 1 bock tall as you can jump onto them from the block below.

i'm not sure if this was intended or just a feature fogotten to implement?

i'm playing on quark and autoreglib 1.12

actually, after some experimenting, i figured out that if you place a new stone wall under another, like this

then you can jump over the top stone wall, but this issue is does not happen with the fences and stone walls in original minecraft.

I can reproduce for vanilla walls with the exact same setup you have there.