You don't say anything about your humidity level. This one definitely wants high humidity, like 85% +. It probably needs a more moderate filtered light level, definitely no direct mid-day sun. Your temperture range is higher than optimal by 5 or 10 degrees too. Expecially if your humidity is low too it adds up to a plant that is too stressed to thrive. Since it seems to be survivng well try a lower light level, the easiest thing to change, and it might be happier. The current spike may be beyond saving, but give it at least 6 months under the new conditions to see if it improves.