As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LEFT BLEED DUCT LEAK ILLUMINATED. EFTL BLEED LIGHT ON MOMENTARILY WITH APU BLEED ON ONLY. ACCOMPLISHED VISUAL INSPECTION ACCESSIBLE DUCTING FOR LEAKS, NO LEAK DETECTED. REPLACED M691 BLEED CARD AS PRECAUTION. NO LIGHT AT THIS TIME, OPS CHECKED NORMAL.