My money bowl caught fire during a spell. Should I be worried?

Treat it as a fire hazard, not a sign you need to interpret. Make sure the bill and anything around it are fully out and cool, and check for lingering smoke or smoldering. If anything is still burning or the fire is spreading, leave and contact emergency services.

For next time, keep paper, herbs, and other flammable items well away from candles. You can leave the candle out of the bowl, use an LED candle, or choose a nonflammable token instead.

A dollar can catch quickly when it is close to an open flame, so I wouldn't repeat that setup. Put candles on a stable, heat-resistant surface, keep them in sight, and extinguish them before leaving. The fire itself doesn't establish anything about the spell's meaning.