UuA can be somewhat problematic but POUG has never been problematic. AUP, I believe, has almost always been problematic as the ticket is generally not reissued.

But that is not the problem here as discussed above - it's the same routing multiple times in a day. That is definitely NOT a normal thing to do and we cannot expect BA to be able to auto-credit that.

Same-day return is usually not a problem either (I certainly have not had any problem). It's flying A to B twice or more in a single day.