Burning Inscription uses base Area of Effect

When using Burning Inscription with a curse, Burning Inscription uses the spell's base Area of Effect rather than its modified Area of Effect. I for one consider the best thing to do with curses to be increasing the Area of Effect as much as possible, which results in a massive inscription with a tiny, disappointing fire in the middle. It's not very effective.

If fixing this apparent bug makes Burning Inscription too powerful, my recommendation would be to adjust its effect to be a circle around the edge a la Fortress. It would avoid this strange disconnect between the spell being used and the effect of Burning Inscription, while avoiding being able to turn any curse into a field-wide Ignite.