I am using a --- STREAM WRITE call on a file that is > 2GB. It doesn't crash or return an error code, but it doesn't write to a file either

The STREAM WRITE subroutine uses the standard fputs() function (part of the C Runtime Library). That function is limited to files smaller than 2GB in size. If you want to write to a larger file, you'll have to use a different API (that means that you'll have to write a C routine and CALL that routine instead of using STREAM WRITE).