I was having this problem just last night with a migration. I don't
know why it happens, but I can tell you how I got around it: I changed
the iteration number of the migration file itself. In other words, I
had a file called 001_create_schedules.rb; I renamed the file to
002_create_schedules.rb.
I guess that is more of a workaround than a solution, but it might keep
you running in the meantime until you can get a more in-depth response
here in the forum (I'm a newbie too).