Zvezda has been leaking since 2019. That doesn't seem sudden and without warning to me. I imagine its going to continue to leak until the ISS is decommissioned.
The return of the leak was relatively sudden. They had done temporary fixes that brought stable pressure for a while, and when it reappeared, the leak jumped back to 1kg/day quickly.
The return of the leak was relatively sudden. They had done temporary fixes that brought stable pressure for a while, and when it reappeared, the leak jumped back to 1kg/day quickly.