Custom fields filling from SDK

Hi, We are trying to auto-fill custom fields for users upon ticket creation however it doesn't seem to be working. Can you assist?

This is the code we are using:

RequestActivity.builder()
.withRequestSubject("Test subject")
.withTags("test_app_error_code")
.withTicketForm(
10872807131281L, listOf(
CustomField(
10872435920913L,
"test-${UUID.randomUUID()}"
)
)
)
.show(context)

Thanks for your assistance