The bottom one might want for a bit more fat, but both look healthy. I guess it could be something about the gecko, her temps, there are a lot of factors. I would say, if she is only producing one egg and then laying it. (Meaning she's not producing two and either holding one or reabsorbing one.) It could be she might have some problems with one of her ovaries, especially if she always produces from the same side.
Try to monitor her, make sure she is only producing one egg and see if it is always on the same side. You could consider taking her to the vet to check on her reproductive system, but I'm not sure how much they could really do... they might remove the nonproducing ovary and test for cancer or infection. I'm probably reaching a bit there, I would guess there really isn't anything that serious wrong with her.
That is the best I can offer. Could just be her way. Good luck, sorry I'm not more help.
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0.1 Albino Leo Gecko
0.1 Crested Gecko
1.0 Dear Boyfriend
Departed: Harvey and Spock