Corner pin data question

when i paste corner pin direct on non 3d text layer in after effects it seems to work nice

or maybe pre composed 3d text layer it works.

how ever when i paste the corner pin data to null and then attach text layer to null , the text gets inlarged or dont wory perfectly why

Corner pins aren’t meant to be “linked” data, they’re meant to be put onto precomps or on to layers. You won’t get good results placing them on nulls.