Initial phone call 30 - 45 minutes went very well. Recruiter asked me to complete a design exercise and told me after it was complete, they would have a response within two days because they don't like to keep people waiting. Recruiter asked me when I would have the assignment complete and I said 3-4 days. Completed it in 4 days, and went way beyond the initial ask of a PSD/Sketch file and delivered a fully designed and working prototype built in html/css. I shared this work with some former colleagues (senior and lead designers) who worked with me at a very large, household name company. They critiqued it and I made tweaks before submitting - everyone thought I'd done a smashing job.
The recruiter didn't bother to mention that she'd be on vacation the next week (even though she emphasized the 2-day turnaround for feedback), and after a few days of no response I decided to contact her boss. I followed up several times after this getting the run-around and after two weeks of this I checked in again.
I received a dry email saying my "skills didn't match" what they needed and that they couldn't provide any type of critique or feedback because of an HR policy. Not to toot my own horn but I'm more than qualified, experienced and talented for this position. Waiting two weeks just to hear a solid no after going extraordinary lengths is incredibly rude. In the end it doesn't matter - I have an incredible job offer in hand, so it's all good.
Lesson learned: don't spend too much time/effort on design assignments when trying to get a job. Your portfolio should speak for itself. There's nothing wrong with a small assignment but red flags should go up when they ask for a bunch of work.