See https://grafana.wikimedia.org/d/000000366/network-performances-global?panelId=18&fullscreen&orgId=1&from=now-30d&to=now and screenshot bellow:
Since 18/06, the Swift servers are showing a significant increase of TCP retransmits, from < 0.1% to >3%.
Even though it's not a high %, it could be the symptoms of a larger issue and have a performance impact.