Halloween mask Carrot

Thank you all for your helpful and kind answers I will try different soil but I don't use manure I use garden compost, Grass, cuttings, small branches and some veggie waste from house, I haven't seen carrot fly this year....
I did grow my latest by putting them as a single seed into 3" containers in BQ compost then put them in the garden as single plants perhaps that compost was no good and that's why I have this problem in some of my carrots this year, I done it this way as last year I sowed a seed of carrots in a tray but transplanting these carrot seedlings to the garden when still young is where I went wrong (so the allotment people told me once) they said "when I pulled the carrot seedlings out of the tray I would have broken the main root that ends up as a carrot, when this happens other small roots will grow to take the place of the main root, that's when you end up with 4/5 smaller fingers of carrot on one plant" so I don't want to do that again (hence the single pots)
But I have pulled a couple of carrots today and 2 were lovely so I'm doing something right but I did say I would post pictures of any unusual looking carrots to see if you can tell me what's causing the problem to my carrots kind regards Kenn

That's a scarey one! The RHS site has some advice on this subject(just had a look) - one reason I'd never heard of was sowing too early!! Have a look at it.