I applied online and spoke to a recruiter first, he asked very basic questions and didn't test my technical abilities at all: work location, get a clearance, salary expectations - very basic. I was then called back a few days later and asked if I was interested in another group - I had no idea what they were talking about and he just said several directorates do ML work. I was issued a coding test for one team. I was asked to prepare a presentation regarding a technical topic, but then I was told I had to interview with multiple teams on different days (present the same thing twice). I was basically being asked to take off 3 days of work for an interview. I meet with 2 teams or maybe 3 who all had machine learning and artificial intelligence work - they all had very different team cultures and expectations.
I was dressed professional but the recruiter had on red chucks and a flannel and the technical team was dressed down as well - seemed unprofessional. They shouldn't make you dress up if they don't.