Why does my 2026 Roth IRA deposit have three different availability dates?

Today $50ish is available. Tomorrow $6,600 available. Then the rest a week from today

just wondering why that is instead of $7,500 being available at once? Either today or tomorrow

thank you!

wanted to spend it all soon but guess I will wait until the 15th? I always just buy once per year after I max it out (VOO)