christ aye that's duff beans man for sure.seems to be getting more common, your def best cutting your losses.
was there not a lad on this thread saying his plants were at 7 weeks and just showing hairs? fuck knows, im wankered.
ive known a few plants do it though. A mate of mine grew a load of low ryder 2 that were half haze, ended up with half a dozen pheno's that just kept growing, wispy buds that half the hairs turned and then new growth started. he got to 6 months and chopped them, all 8 ish oz. things were 6ft odd no bother. i did a sativa that went 6 n a half months not long back too.