Thanks for all the comments. The confusing part is that Avianca (Aerogal) , the operating carrier, said over the phone there would be no charges, but Untied, the ticketing carrier, said there would be or maybe. Guess I will wait and see.
The operating carrier will make the decision. It is the one that matters.
The ticketing carrier (UA) phone agent may not know and is just making it up to cover up the lack of knowledge. Best to ignore.