Juvenile molts are done by 6 months....but maybe that could be different for birds hatched in late summer, but I doubt it.I've never seen birds molt in the fall, it's always been late summer or late winter.
There are several molts during a bird's first year, the biggest one is about when they hit a year, give or take a few months.
Several of my year olds months are molting right now and they look like heck microwaved.
It could be something to do with which part of the hemisphere you're at.
Yes, late summer(like now) is not an unusual time for molting.
Have never even them molt in summer even in high heat, tho here in MI is not as high as in AZ.
There can be a lot of exceptions, but this....
Is not an accurate blanket statement.They're molting, it's both summer and their first birthday so it's about time for it.