Can acid reflux cause low oxygen saturation as seen in a pulse oximeter?

No. O2 saturation is related to lungs. Get the instrument checked for accuracy and try another one if still low see MD

No, it is not likely that acid reflux would cause low oxygen saturation. Follow recommendations from the doc who suggested checking your oxygen saturation.

Not per se. Acid reflux as an isolated event would not affect oxygen saturation. A long standing acid reflux could damage the lungs if the refluxed material gets aspirated into the lung repeatedly.