Before my last race I was on lvl4 for Development and I needed a further 40XP to level up. After that race I am still on Lvl4 for Development and it says "Level 5 in 0XP" when I hover my mouse over. This is weird...
This is common, you'll rank up to Level 5 in the next race. It's not a major problem, just a small setback for development reasons, but you'll still rank up.