He literally just pointed out the fine print that shows the 1986 Vienna Convention is "not yet in force."
If you need it in bigger font, here's the handy dandy Wikipedia article on the same.
"Article 85 of the Convention provides that it enters into force after ratification or accession by 35 states. As of October 2022, the treaty has been ratified or acceded to by 33 states. As a result, the Convention is not yet in force."
Given that 2022 is after 2015, it's impossible for the 1986 Vienna Convention to have been in effect during 2015, as you so confidently asserted.
The most recent Vienna Convention establishing international norms on treaties, therefore, is the one from 1969.
Yes, you are right: The 1969 edition is the operative treaty.
However, many parties reference the 1986 edition to make their case, even though it has not yet been officially ratified. That reference goes both ways: The 1986 edition includes international organizations as appropriate parties (which would have included the OSCE); but since the 1986 edition has not yet been ratified by 35 member nations it is not controlling (though it can be referenced); conversely, its non-ratification can be a counter-argument.
The fact remains that the Minsk Agreements are NOT treaties, no matter what woodpusher claims.