Handheld item not showing default animations

[RaccoonSanttu]

I'd like to know how i could get back my default minecraft animations, like for example my handheld items normal position for one of the arms. Of course i have this picture as a reference as to what i mean by comparing both hands, you can see that both are holding blocks but the primary hand hasn't moved to a position like the offhand. which is really odd. i'd like to know if there is a fix. I am using a 1.12.2 Blockbuster mod ver: 2.6

Also when holding a Bow that is suppose to have a pointing animation. it doesn't move from that single position like a statue.

Any ideas or theories? Because i sure am bothered by it. & if its not possible to fix then i guess ignore me.