My first two BP clutches were subjected, intermittently, to massive temp spikes as I struggled with the concept of "friction" (thanks again to Dr. Del, who eventually reminded me that Fan --> friction --> heat ....)

I did lose most of the eggs, but a couple made it. There were no deformities, but the spikes didn't start until about three weeks prior to hatching, if I recall correctly. I had repeated spikes, not just one isolated incidence, though I think most spikes were in the ~90-95 range and only once did it get ~98.

I would imagine that your younger clutch is at higher risk of death and/or deformities, since they are still in that very vulnerable period of development.

Best of luck with the remainder of incubation!