It's a notable drop rather than a blip, according to Samir Madani, cofounder of TankerTrackers.com. "Russian exports have been moving steadily up until now. The two biggest visible snags are in the Black and Baltic seas. Pacific and Arctic regions remain unaffected, at least for now," he said.
As well as the apparent falloff in exports, there is also a traffic jam of more than a dozen oil tankers in the Turkish Straits, caused by a dispute between the local authorities and maritime insurers due to the sanctions and price cap.