Well, at the very least it could make the output unreliable.
Not at all as your sending the same signal to 2 independent devices, remember there's no flow control or an thing. Take a look at the Wireless/SD shield in the products section this is how it works.
@OP do you have any links to a data sheet that would help a great deal. A photo of the "cable" and the socket on the CHU would help.
Mark