You’re in Week 5 of flower with Papaya Sherbet, and yellow/purple fan leaves this early usually point to a mild nutrient issue, not natural fade yet—especially on a 9–10 week strain. Your EC is at 1.7, pH is solid at 6.4, temps are decent (22°C day / 21°C night), and humidity is around 60%, so the environment looks pretty stable.
The yellowing likely means your plant’s using up nitrogen faster than it's getting it, and the purple could be early phosphorus deficiency or just the strain showing color under stress or cooler temps.
You’ve got 4 plants under an EVO3 LED in a tight 2x4 tent, so they’re probably feeding hard under that light. If buds and sugar leaves look good, no stress—just try adding a touch more N and maybe a little extra P/K for the second half of flower. Keep pH and EC steady, and you should finish strong 💪
Let me know your feeding schedule if you want help dialing it in.