Yes, but a cutting taken while the stock plant is flowering will need to be forced to revert back to a vegetative state under 24 hour light. This causes additional stress, slowing growth and development. Rooting may take up to three times longer when the cuttings are taken during the flowering cycle. The cutting may not have enough stored nutrients or carbohydrates to survive. If you must do this then take the cutting when the mother plant is only a week or two into flowering.