I would try changing the nesting substrate maybe its just not right for her and could be reason she holds them for so long. I see you got 3 locations at different temp zones which is good. My thoughts would be either leave those nests and add a second right next to each with different nesting substrates and she what she chooses and add deep substrate to the bottom as well.I would also use hollow tube that gets narrow towards the bottom hanging vert with little substrate in it also. Whole cage nesting is what my goal would be.

Did the 2 full term eggs pip ? indent when they got close? was wondering if it could be something else to cause them not to hatch other than being weak.From pic i didnt see a egg tooth.Also the egg shell looks thick maybe its me do you supplement the diet for the female and provide UVB ? Maybe slit egg when its close like python guys do to help them emerge with better results.

Good luck on this next clutch 40 days is little better i think you will have better results from this clutch maybe a low percent will hatch.