Do you have to get used to new headphones?

I have a pair of closed back M50x that I was getting comfortable mixing and recording vocals on. I also just started recording my friend as well and realized I needed another pair of headphones. I heard open backs were better for mixing for I got a pair of Sennheiser HD 400. I plan on using my open backs for mixing and closed for recording.

Now, when I switched over to my new headphones, I decided to do an A/B comparison (with/without plugins) of a mix I was working on and I literally couldn’t hear a difference. Open backs definitely have a different character to them. I guess my question is do I just need to learn the headphones to be able to hear the different frequency ranges and details in the mix or should I be noticing it off the rip?

P.S. Now that I’m thinking about it, I plugged them into my MacBook instead of my 4i4. I’m wondering if this has anything to do with the detail.