"I have gone to work early."
Translation:Dw i wedi mynd i'r gwaith yn gynnar.
I have raised a Duolingo bug report about "collnod èr". Thank you, @ibisc, for explaining. It's strange, but neither my question nor your answer seems to show on the discussion at the moment, though I did get an e-mail with your answer. I didn't get any acknowledgement of my bug report either, but we live in hope. Thank you again. Great course.