Blue gouldian not fully moulted

[Jebtech95]

Hey guys quick question. One of my blue cock birds was bred January 2023 it’s now been over a year and he still isn’t fully coloured. I’d say he’s about 80-90% complete which I found so strange. Guy has produced two clutches this year, what’s going on

[finchbreeder]

So I am guesing he was the last chick of the season.
Because my Mother had exactly the same thing with her last chick of the 2022 season.
By strange coincidence he is also a blue cock bird.