Help plants not budding

Ok i need some help.. I started 6 autos 14 weeks ago. I was hoping they would be small and fast but i was wrong they're the opposite they're slow and big. I'm thinking it's because of the big 20ltr airpots I used. I did 4 big bang and 2 blue cheese. The big bang is done and drying but the blue cheese isn't doing much, they showed signs of sex early and could see where all the bud sites were going to be but didn't grow any white hairs after 10 weeks, i tried switching to 12/12 to see if they'd given me normal blue cheese and they grew white hairs but then i switched back to 18/6 to see if they'd go back into veg and cos i had other autos. They didn't go back into veg but they don't seem to be getting much bigger and there is some heat stress and yellow burns on some leaves I've tied them down now but not sure whether to bin them or whether they could not be autos? Is that possible if they havnt gone into veg? Anyone help? I'm thinking they might be dud plants?

I used 2 600w cooled lights in a 5x5 tent 2metres high the plants are both 1.6 metres out of the pot. I had to switch them to another tent i borrowed as there was no space the new tent had 2x 250w uncooled lights with in and out fan. They're back in the original tent under the 600's but still not doing much after 4 weeks of buddin

What medium are you using?

I didn't think you could alter when an auto flowered.

Using bio bizz lightmix with dutch pro nutes grow and bloom A+B