It could be a different plant...a seed got into the mix by mistake. It happens. If you're adventurous and the plant looks healthy, see what it grows into. Maybe it's a weed. Maybe it's a different sport of some plant.

Susan, thank you for your input.
So this is not "damping off"? I have always understood it as that affecting stems but I did see one photo of damping off via Google that showed dark/black leaves instead of the stem buckling over.

Not sure what to think but I guess I'll keep them growing to see if they live or die. If something is wrong, I suspect it's too late to cure them. And I have too many seeds to spend time curing ones that don't want to live, right?

Or maybe it's the soil mix I used. It was a really gritty variation and perhaps it was just a combo not much liked by seeds though the speed of germination said otherwise,

Thanks!

This is a very bizarre batch. Maybe it's the mixture of soil I used, or maybe it's something else. It's not the seeds, as the previous round of this all sprouted and are growing wonderfully.

I planted 12 and 5 never came up, 6 did as shown above and eventually withered completely (and still had green stems!) and one looked okay. I cut it off that cell pack (and threw the rest out) and took care or it with my other seeds.

This is today. Not only is it not vigorous, it's beginning the whole browning/dying process.

Any ideas what is happening here?

A closer shot. Sorry, this is about as good as it will get on my iPad.