Video Example (First Person View): https://youtu.be/FbYD2-p5lMg
CPM Version: Forge 1.12.2

Edit: Forgot to mention that this only seems to occur with "solid," whole blocks. Tree leaves and Slabs don't cause any suffocation from jumping up at them.

As seen, I cleared my player model thinking this was only an issue with the custom models I was working on. No matter my adjustments to their Bounding and EyeHeight properties, they suffer this for Survival Mode.

If this can be fixed with any specific numbers (or number combinations in Bounding's arrays), it would help to know what does this! However, I don't know what these can do when the cleared, non-custom model is having the issue as well.

I have tested this exact thing without CPM as well. It strictly happens with this mod and no other that I'm using. It doesn't occur in Vanilla Minecraft either, of course.

Only one of my custom models is exempt from this because it's a small critter, so its properties are smaller than even the cleared/vanilla player model. Could there be a slight numerical mistake for the vanilla player when it's interacting with this mod?

Until this can possibly be resolved, I will tread this mod with caution in Survival and give my friends some heads up on when we play it together sometime this month or next month. Been having tons of fun with this mod otherwise!

Thank you in advanced for your time looking into this when/if you do.