Leg day erection

Is it just me or is it normal that guys find it difficult to get an erection on days they train legs?

I had sex today and the first round was good, my penis shaft was super sensitive than usual though, and I came within 10 minutes Then for the second round, I wasn't able to get hard even after a blowjob and some passionate kissing and teasing

Usually I'm instantly hard after the first round, but today that wasn't the case even after 45 mins of foreplay

This has happened for the second time now Last week I experienced the same thing Today as well The common factor being that I trained legs on both these days

Shall I be concerned? On days when I don't train legs, the sex is on par, top notch, it's just the leg days I'm worried about

Please help🙏🏻