Im no expert but i wanted to share that i had a similar experience with my macaw when she was about 5 months old, she started regurgitating her food, at first it wouldn't be often but then she slowly started doing it daily over the course of the week and i had tried everything thinking it was the temperature or amount of the food, i ended up taking her to the vet because i noticed weight loss, which is normal when fledgling age but it still worried me, they had to do several tests and even a x-ray to see if anything was wrong and although nothing came back wrong the vet assumed she must of had a slow crop, so he prescribed two different meds and in a week she was all better. What im saying is, just keep a close eye on her, maybe give her less formula and make sure shes really eating her food, monitor her throughout the day , but if you see no improvement definitely go to the vet
