Scrum: Is it ok for the design/UX of user story to occur in the same sprint as implementation

I am currently in a sprint (two week) where the designer is tasked with defining the requirements and UX of a particular user story.

In the same sprint I am to implement this design. During sprint planning I had to take a wild guess as to how long this undefined user story would take.

Today I finally received the design. Unfortunately the design is incomplete/vague and is more akin to a clients requirements than a design. However from this I can still see that I have not nearly estimated enough.

To make matters worse this is not the first time. In the last sprint the exact same thing happened. I flagged it in our retrospective and the scrum master did not have an answer of how to solve this, instead saying "that's just development for you". Ironically he gets annoyed if the burn down is not on target...

Now I am going to have to ask/work with the designer to get his job done. This is going to hold me up as I have completed all my other tasks.

So my question is

• A) how do you handle dependencies in sprint planning?


• B) how should I now approach the sprint? Re-estimate the current user story and watch the burndown turn into a burn up and be viewed as incompenent/unproductive? Or add a new task to the current sprint along the lines of "help the designer create a suitable design"