Online real estate company Opendoor Technologies (NASDAQ: OPEN) has stunned Wall Street in recent weeks with a blistering rally, drawing attention to the momentum’s sustainability. Notably, at the close of the last trading session, OPEN stock was valued at $9.07, down nearly 14% on the day. However, on the monthly chart, the stock has surged 274%.OPEN one-month stock price chart. Source: FinboldDespite the sudden rally, CNBC’s Jim Cramer is urging caution for investors eyeing Opendoor stock.On his Mad Money ...