From the last page of the thread linked above…
https://forum.nasaspaceflight.com/in...393#msg2266393
Okay, I read the N+1 article, and here's what I understood: telemetry information shows that due to increased pressure the bellows of the fuel tanks have ruptured (yeh, the same bellows that were contaminated and cleaned for years). This caused some of the fuel to leak. A a result, N+1 reports, Nauka may not have enough fuel to dock to the ISS. We hope this is only a telemetry error, not a real issue.
https://forum.nasaspaceflight.com/in...396#msg2266396
If the bellows have indeed burst, would that be end of mission?
Regardless of any other method to move Nauka to the ISS (RCS thrust, dock a Progress to use as a tug and push it up, etc), if there is now no barrier between the fuel, oxidiser, and the pressurisation system, and no way to drain the propellant tanks - which would normally be purged via pressurant pushing on the bellows, just dumping pressurant into the tanks without them could cause a bubbly mix of propellant to remain in the tanks rather than venting - attaching Nauka to the ISS would mean attaching two containers with a large volume of uncontrolled hypergolic propellants.