As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
BLEED AIR WILL NOT SWITCH FROM APU TO ENGINE BLEED AIR IN FLIGHT, THEN VERY HARD TO GET BACK ON APU BLEED. RETURNED TO SLC. REMOVED AND REPLACED APU LOAD CONTROL VALVE IAW MM 49-51-01. RAN APU AND LT AND RT ENGINES. ALL OPS CHECKS GOOD AT THIS TIME.