Hi,
So I use 1.0.2 of your pack but weirdly the texture looks bumpy with HRR 2.1,
I am using 1.16.5 with latest version of OptiFine, I have another pack as well which brings a dark UI to Minecraft but I don't think that is the issue.

Screenshot :

Parallax Occlusion Mapping should be set to On if you want to see the 3D effect I guess

I was able to disable it, or to use "pixel perferct bump" instead of the smoothed one and it looks quite good actually.
Before closing the issue, I would like to know if those settings are correct to use with your pack :

EDIT : does disabling parallax occlusion mapping messes up in any way with the effect (cobble stone for instance) ?