There is a phenotype that presents in autoflowers where the plant keeps growing and making new pistils but doesn’t make hardly any resin (Trichomes). I had one several years ago and I know there is a few others mentioned here on the forum last year. It has nothing to do with your system. If its the same pheno then it will just keep on stretching and making new growth but it will never finish. Here is mine after 17 weeks. One grower waited over 25 weeks with no real buds. You can try to wait it out but if its the same issue it will never finish.
You can see two in front that were normal autos, but the one in back grew like mad and I kept bending the branches down. After 17 weeks I pulled it.
Here is another…