Config impacts in prj.config

Trying to set up UART/UART0 for async.  I cannot get the uart interrupt config to shut off.
CONFIG_UART_INTERRUPT_DRIVEN=n  is set in the prj.conf 
In config output, this field is still set:
CONFIG_UART_INTERRUPT_DRIVEN=y
I do not have access to Kconfig as this is being set up on the Laird/Ezurio Pinnacle 100 DVK which uses and out of tree build.
How can I see which config is locking the Uart Interrupt Driven on?
Thanks
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