I’ve found a seed! No males no herms? Help! :s

this is my first grow, northern lights femanized, I noticed a seed in my trim, I’ve had a scan through my buds and I’ve not found any seeds in them,
I’m still a little worried and confused I’ll have to go through the buds again to find the offending bud,
I checked the plants throughout the grow and none turned herm that I noticed
Does anyone have an idea as to what is going on?
Thanks

I've seen a male flower sac develop within a pistiled calyx on a reversed fem, where the bananas emerge from the calyx (in reality there is a male flower housed within the calyx, and once you peel the calyx back, you can see the male flower sac). The point being, if you are on the lookout for male flowers in your buds, they may be hidden within calyxes.

I have also found a couple banana peels deep within a bud that could not be seen until i broke the dried bud apart later. I imagine when this happens from deep within a bud, pollination will be sparse as the bud density and surrounding resin minimizes pollen float away, hence the single seed. These are only possible explanations though. let us know if you find out for sure.

Cannabis, as a dioecious plant species has a huge propensity to self propagate. As Zero-OS has mentioned the means for this self propagation is not always easily seen and in many times quite carefully concealed. Couple this with a 'feminized' plant and you're increasing your chances of this phenomena. I wouldn't sweat 1 seed and I wouldn't bother trying to find the offending flower. Smoke and enjoy...and for shits and giggles...sprout the seed and see what you get.

You probably threw a Nanner or two

A “nanner” is a pollen sack that grows, embedded into the bud. You might find these near the top of the plant, right in the buds. “nanners” are simply pollen sacks (look like tiny cluster of bananas) that form in late flower. They grow near the end of the plant’s life. Again, this is mother nature’s way of attempting to pro-create.
What to do if you find a “nanner”?
Nothing. Don’t worry about it. In most cases, the pollen sacks don’t have time to mature and they never open. If they do, it is usually too late for your female to become pollinated anyway. Unless, of course, you have other females in the flower room at an earlier stage of flower. Again, late flower pollen sacks are more prevalent in certain strains. If they cause a problem, don’t grow that strain again.