Wow I never would think that flannel a suspect bleeder like that. Just out of curiosity, do you have a water saving front loader washer? Sometimes they don't use enough water to fully suspend loose dye particles. I am thinking that may be a reason you had to run it through so many cycles.

No. I have a 15+ year old regular washer with one of the largest tub sizes available. I'm shocked too. This is my first experience with fabric bleeding to this extent. I don't really understand.

After it dries I'm going to make a tiny quilt with all white fabric, wash it and make sure it's ok. Even if it is, I'll use dark fabrics for the "real" quilt I'll use it on.

What a cute quilt. I'm glad that the spots came out. I'm shocked that your backing fabric bled. I expect it with a solid, but not with a mostly white print. Thanks for sharing your experience.

Wash your remaining fabric in Retadyne to set the color! I hope this helps!