@Jean-O ..if it is over a few different crosses I would find it harder to problem solve too......but I have had what we desribe as Fast Flower pop up in the Autoflower Line....
It is Neither Auto or Photo coz it will Flower and Finish under 24 hour Lights....but like a photo it seems to go back into veg AFTER flower...which full Auto doesn't...but then..according to current profiles...Photos won't Finish on 24 hour Light...and these plants Will....
They take Longer...and they are much Bigger.
I Know
@FullDuplex utilised it in some of his Monster sized crosses.....and if I'm not wrong...it was what Stitch used in his Super Auto line....
I can even Pin-point some Tips to Stop it getting into a Line............But....with it happening over Different crosses...makes me Think Not...unless you did a mass pollenation somewhere.....
That is how I got it.......1 Primo..primo Stud Muffin.......and I let him have his wicked way with a few.
If a female does it...she flowers and goes back into veg...you can pick it up....
Much harder with a Male.....coz it flowers......and we tend to use them as soon as they are pollenating..so we don't See the male go back into veg.
Simplest Trick if Anyone is doing their own crosses is Never use a Male that comes into flower after day 24.
The Problem is...when they males come they are Stunning....the essence of Hybrid vigor......
....makes them an Obvious choice for Stud.
Sorry I couldn't be more Help......