Bc. Hawaiian Wizard turning dark brown?

[iamppdoc]

This was a division from a larger plant, about 2 months ago. The plant looks healthy and is in a moderately low light part of the green house, about 2000 fc. when there is direct sun Two weeks ago the newest leaf began to turn brown, like the change you see sometimes from too much light. Within a week the whole leaf was dark brown in color but still well hydrated and "waxy", and looked otherwise healthy. The other leaves show no evidence, to me, of light damage and where this plant is, it is hard to believe that is the cause. Any ideas?