In any large spawn, there are going to be some defects. And unless the breeder inspects very closely some are not initially noticeable , and are not culled even though they should be).
Some are not noticeable until the fish puts on some size.
I would consider that defect on yours minor
If you are just keeping it because you like having a JD, no problem.
But I would not breed it, because it may pass on that same defect thru generations, and its is t could not be entered into a fish show/beauty contest.
Below is a shot of some Tomocichl asfraci fry I bought very young, more than a decade ago.
You can see the one far left, has some serious defects (it barely has a mouth), but even as the others grew, more and more defects came into view.
Turned out they all had defects.

Below one the grew to a semi-adult, at the time I had bought 20, hoping to get a spawning pair, but in the end, I would not allow any to breed (even though at the time they were considered quite rare). And any other aquarists that had picked these up at a the time, had the same defects.

Sometimes these defects are genetic, sometimes they come from water quality issues when first hatched such as an ammonia spike, or high nitrates among other anomalies, without knowing for sure, allowing them to breed could be problematic.