This is stated in the ISW report.
Experts note that the Russian Ministry of Defense seems to have shifted the priority of the Bakhmut offensive in favour of preparing for defence against an expected Ukrainian counteroffensive, which has put the Wagner Group and its founder Yevgeny Prigozhin in a potentially difficult position.
Prigozhin released a series of videos on May 4 and 5 announcing that Wagner's PMC would withdraw from Bakhmut on May 10 if it did not receive the necessary supplies, and launched particularly harsh and emotional attacks against the Russian Chief of the General Staff, Army General Valery Gerasimov, Russian Defense Minister Sergei Shoigu, and the leadership of the Russian Ministry of Defense in general.
The report points out that despite the shift in priorities of the Russian Armed Forces leadership, Prigozhin did not stop trying to completely capture Bakhmut.
According to the analysts, Wagner's continued hold on Bakhmut is inconsistent with the overall slowdown in Russian offensive operations in other parts of Ukraine, as regular Russian troops appear to be shifting their focus to preparing for the long-awaited counteroffensive by Ukraine.
With the exception of very limited and localised attacks near Kreminna and near Donetsk, Russian forces have largely ceased offensive operations across the entire battlefield, which likely means a shift to defence.
"It would be an operationally sound decision for the Russian MoD to begin withholding and stockpiling ammunition and supplies in order to prepare for any Ukrainian counteroffensive actions, and Prigozhin’s desperate statements indicate that the Russian MoD is likely doing so," the review says.