Hello,
Which version of Fluent are you using? The operating pressure in Fluent is always set to the default 101325 Pa which is 1 atm. The results you obtained will be always regarding the absolute pressure = guage + operating (atm pressure). Therefore, if you forgot to set operating pressure to 0, I don't think that it will be a problem, if the absolute pressure value itself is intended. But if you have input the absolute pressure as a guage pressure in the BCs, then I think you might need to re-run the simulation.
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