Juvenile Bearded Dragon Passed

I know this has been asked but I’m struggling to find out what went wrong… I have had beardies before, currently have one that is 13 years old and lost one last year at 10.

We got a young one at the beginning of November 2025. Alert, active, ate well until yesterday where he didn’t move too much. I just got home from work to find it it in the usual basking spot but it’s eyes were sunken and obviously passed. Some salad was eaten at some point today.

It was fed a diet of dubias, crickets, and greens, and we used calcium powder. Basking spot was 102°, we have a 22” reptisun 5.0 HO uvb bulb. Substrate was 50/50 play sand and top soil.

I guess my question is what would cause the sudden passing…? I’m at a loss as to what went wrong