Here are the most common portfolio presentation mistakes I see being made. Since this is the most important part of your interviews, it's the ultimate closer for your offer. If you don't impress while pitching your work (no matter how great), the rest of the interview will fall to the wayside.

PROCESS NOT PROGRESSION

This is the most common mistake I see from junior designers, where they are obsessively focused on showing the step-by-step process. Instead, you want to highlight the most interesting moments that contribute to the overall story. Think of this as the equivalent of a film adaption instead of real life.

OVEREMPHASIS ON VISUAL DESIGN

Contrary to popular belief, product design is about solving hard problems, not  just to make things look visually appealing. Your priority should always be storytelling that aspect of yourself as a product designer.

TOO MANY VISUAL ELEMENTS

Keep your presentation simple so that your designs can shine. Too much noise will detract your audience's focus and increase cognitive load, making it more difficult to follow along.

USING A FANCY PRESENTATION TOOL

After using Figma's prototyping tool to make something look cool because that's what other designers were doing, I realized how buggy it could get and the time it took to fix issues. Stick to something that's reliable above all else, so you're not in the middle of an interview with slide issues. Choose a common presentation tool like Google Slides or Keynote. 

TOO MUCH TEXT ON SLIDES 

Save your text for your own notes. Keep slides as clean and minimal as possible, so that your work stands out. This also makes it for your audience to comprehend what you're storytelling instead of trying to discern the information.

TREATING YOUR PRESENTATION LIKE AN AFTERTHOUGHT

Instead of spending weekends on your portfolio website, you should be putting that dedication towards your portfolio presentation. This is the most important part of your final interview, forget about getting the offer if you did everything else well but didn't impress with your portfolio presentation. This is the ultimate closer for product design jobs. 

Why is no one teaching this, if this is one of the most important interviews for landing the job? Especially bootcamps promising jobs?

I theorize because: 

1) it requires a lot of hands on time, which bootcamps aren't willing to do for efficiency. They would rather follow a standardized or cookie cutter curriculums.
2) It requires bootcamps to hire product designers who are willing to teach how they have landed jobs with portfolio presentation. They are expensive per hour.
3) Most product designers unwilling to give away their competitive edge.