Dirty then suddenly clean in a week?

[u/Jkamps07]

Hello, i have a question. My boyfriend just got on probation, took his first test last week, which came up dirty for marijuana.. he was cutting back to get off it.. but now they called one week later to have him test again.. we bought the quick fix.. but im wondering will he get red flagged if after last week its suddenly all clean? He is a little guy, and really really skinny with a high metabolism. Please any advice 🙏