Streaking after water dries

Here ya go. Customer just sent this to me. I’ve been doing his house for 6 years. I only put in 3 inches of SH in a 5 gallon bucket with a dash of elemonator. Dark colored siding is funny. It hasn’t rained since I did his house. I’ll go back in a few days and soap it again. Hopefully it goes away this time. He’s worried it’s my soaps that stained his siding.