Currently it parents "builtin/generated"
which makes items huge in world:

Changing it to "item/generated" will fix this:

The above was me changing it in a resource pack to test it.

The change from builtin/generated to item/generated was in 1.9 I believe.

-Mrbysco

Thanks for the fix

No problem :)
I had my gf tell me the items appeared huge when dropped so I went looking and I immediately guessed right :)