Part of mashes disappear

[Vitalii5E16]

Hi all

I have some issue wtih the mash. 

As you can see some part of 3d model is disappear. 

Im using SP v7.2.1, macmin BigSur (latest version).

[Vitalii5E16]

Default shader in project is "asm-metal-rough"

If I change it to "pbr-metal-rough-with-alpha-test" then the result a little bit better but not 100% good.

https://prnt.sc/1c6ofl8