The name of this thread is a bit convoluted I guess, but it was hard to fit in a few words.
The issue is as follows; The Rockbreaker Ox encounter asks for 5 silver bars in return for the Ox companion. I have at the time of this encounter and writing this thread 157 silver bars (which is more than 5). When I got the encounter and clicked the option to make the trade I got an error message saying I didn't have enough copper bars (despite the prompt specifically speaking of silver bars).. However, even then I have 7 copper bars in my hoard. So something is going wrong here. Either the prompt is incorrect in both number and type of metal required, or something is going wrong in recognizing and trading in the items, and the text in the error message is incorrect.
I have been able to succesfully do the trade two or three times prior, and many more times during EA, so I'm not completely sure where it is going wrong this time.