In 2014, during the Battle of Ilovaisk, they agreed to let surrounded Ukrainians withdraw, then they massacred them.
As observed by the Heritage Foundation:
“Russia has rarely, if ever, signed an arms control treaty that it did not violate. Russia is in violation of
the Helsinki Final Act,
the Istanbul Commitments of 1999,
the Presidential Nuclear Initiatives,
an agreement to remove its military from Georgia and Moldova,
the Conventional Forces in Europe Treaty,
the Budapest Memorandum (in which Russia promised to “respect the independence and sovereignty and existing borders of Ukraine” and “refrain from the threat or use of force,” among other things),
the Chemical Weapons Convention,
and the Intermediate-Range Nuclear Forces Treaty (INF).Russia is possibly in violation of the Biological Weapons Convention and the Comprehensive Test Ban Treaty as interpreted by the United States.”
I think Russian phisolophy considers adherence to treaties to be a form of weakness, therefore they go out of their way to demonstrate that they’re unbound by treaties . . . or common decency.