Export script doesnt export entire fontawesome-5

I wrote a batch script to export fontawesome-free-5.12.0-web package in bootstraps assets\css folder. When I export using bootstrap this batch script runs without error but doesnt export entire fontawesome-free-5.12.0-web folder. When I run the same script using command promt - the xcopy works correctly.

My script :

set source="%~dp0assets\css\fontawesome-free-5.12.0-web"
set destination="%1\assets\css\fontawesome-free-5.12.0-web"
xcopy %source% %destination% /E /I /H /Y /J

One possible conclusion is that if there are many files in a single folder - it doesnt export properly.

Sorry for replying so late. I am not familiar with writing batch scripts under windows, but maybe you can test this by starting it in a CMD window and trying if it works when not triggered by Bootstrap Studio.