As per Hiren Doshi's book (Scrum Insights for Practitioners), the PO encourages the dev team to work directly with stakeholders and users for clarifications on a PBI so he or she (PO) does not become a bottleneck.
I would humbly request the scrum leaders to throw light on the above statement. Please correct me if wrong - as per Scrum Guide, the dev team interacts with stakeholders and users only during Sprint Review. If the above holds true, the dev team may also interact with them during the sprint.