I am not sure about that. My friend's African Greys breed all year round. He has almost 20 babies now.
Yesterday, Zico took a different flight pattern from his usual routine. Zico and Eclipse were doing their usual flight routine at the playground. Out of sudden, Zico took a leap up and flew out of sight into the nearby trees. I couldn't see him but I heard his calling. I quickly put Eclipse back in the cage and look for Zico frantically. I heard him flying from tree to tree based on his calls. After a few minutes he returned, landing in front of me on the monkey bars. Probably, he was trying to show me this is what free flight is all about. He really freaked me out.
I called up a few friends who have/ had free flying green cheeks. They said it is normal for their green cheeeks to do what Zico was doing yesterday. For the time being, they will be back on their leashes. I think I am not born for free flying birds even though I have been dying to see my birds to do what Zico could do yesterday.