Not MR could be caused by radar equipment not functional. The aircraft can fly but cannot perform its mission.
https://www.understandingwar.org/backgrounder/russian-offensive-campaign-assessment-march-2-2024
Russian Offensive Campaign Assessment, March 2, 2024
Transfers of North Korean weapons to Russia by sea apparently paused as of mid-February 2024. North Korea-focused outlet NK Pro reported on February 29, citing satellite imagery, that Russian ships involved in the maritime transport of North Korean ammunition and weaponry to Russia have not docked at North Korea’s Rajin Port since February 12.
NK Pro reported that Russian ships have made at least 32 trips between the Rajin Port and Russia’s Dunay and Vostochny ports, Primorsky Krai since August 2023. NK Pro reported that the Russian Lady R cargo ship transported an unspecified number of shipping containers, likely containing North Korean ammunition and weapons, between North Korea and Russia from January 30 to February 8 and that the Maia-1 cargo ship arrived at Russia’s Vostochny Port from North Korea on February 12.
NK Pro reported that satellite imagery has not captured another large cargo ship traveling between the two piers or new deliveries to the Rajin Port since February 12 and suggested that the pause could be due to production issues in North Korea or other logistical issues.
NK Pro noted that North Korea could also be transporting weapons to Russia via air or rail. ISW previously reported that Russia uses the Baikal-Amur Railway and the East Siberian Railway to facilitate cargo transfers from and to China and North Korea, both countries that Russia is increasingly relying on for economic and military support respectively to sustain its war effort in Ukraine.
South Korean Defense Minister Shin Won-sik stated on February 26 that North Korea has sent an estimated 6,700 shipping containers of ammunition to Russia in recent months.
Shin stated that these containers could carry over three million 152mm artillery shells or roughly 500,000 122mm shells.