In the first image it looks like the "disabled" profile has been selected, and then shadows have been manually enabled. Shadows are disabled in the "disabled" profile, make sure they are enabled in [Shader Pack Settings] -> [World] -> [Lighting] -> [Shadows].

I tested both with the same settings and turing on/off the shadow option on oculus doesn't change anything. It always looks like this.

Unfortunately I do not provide any support to oculus/rubidium as they are unofficial ports of iris and sodium. There are alphas of official neoforge ports for iris and sodium, please try those or use optifine.