What is the worst case if USCIS later questions my CPT?

Honestly: a future filing - H-1B, green card - could ask questions about this period, and in bad cases people lose time or redo status. What separates outcomes is nearly always the same three things: real study, full-time status, good records. We build you onto the protective side from day one; for your specific history, that's a senior-consultant conversation before you spend anything.