Sudden death of C. Versicolor sling. Did I do something wrong?

[Ungoliant]

This is an enclosure that I had prepared for when he got bigger. Would it have had enough ventilation for a versicolor?

I would add some more holes on the other two sides and replace the bamboo with something flatter that leaves room for more plants in the top half.

I would definitely be concerned that the gap at the bottom could be an escape route for a determined sling.