I just saw Connor for a new recipe and just bought all the items. Now I can't give them to Mathis. I had no idea you had to go back to Mathis after the hour was up before you could get a new recipe. There was nothing stated that you had to re-visit Mathis before you could get a new recipe and now I'm stuck with stuff I don't need and probably won't be able to resell :(

I actually was waiting for one weapon to be made and bought new items for a new Connor recipe. When I went to Mathis it just told me about completing the weapon. However, after a few minutes I went back to him again and he let me turn in the items.

There does appear to be a refresh delay or cache delay or something. Try going to Mathis' shop from the map and to Connor from the link to the right on the main News page, these seem to always work.

Thank you very much!