Hedged XAUUSD positions led to sudden margin call

I was introduced to a hedged XAUUSD strategy that was presented as low-risk, with buy and sell positions intended to offset each other. Soon after the market opened, the positions suffered severe losses and resulted in margin calls.

The losses were substantial despite the hedged setup. I need a clear explanation of the execution, pricing, and risk conditions that caused the positions to deteriorate so quickly.