I know why, i showed you the beta mars rocket i used on accident, yesterday I was at a wedding so I was more focused on wedding things and that completely phased out my memory of two second stage side boosters I didn't have the blue print of the final mars rocket i used, all i had was the beta mars rocket in the blue prints, so I thought that was the one I used luckily I have quick saves.
Sorry, even with the revised rocket you showed, and adding two variants to the second stage... It's still significantly inconsistent with what's in the journey screenshots.
Please submit a new mission where all the journey, earth orbit and buildscreen screenshots are definitely from the same mission.
Attempt Two
With advances in technology and pressure to beat Elon Kerman to Mars, our scientists have moved the two side boosters down 1 meter but kept the side separators where they are.