Working on abs, but feeling quads- question

There is one video where Daniel explains it, but I can't remember which one.

Today I did this workout: https://www.fitnessblender.com/videos/23-minute-active-static-abs-workout-abs-burnout-routine

It definetly reminded me on why I am working on my core.. The thing is with ab exercises that ask for straight legs, especially in the air: I always feel in high up in my quads. I feel my abs as well, but I often need to relax to ease my legs..

My yoga teacher told me I have a tight psoas muscle. Could that have anything to do with it?

My main question is: what is going on? And what muscle do I need to stretch more often to feel it in my abs more?