"Following the 6-week military hostilities between Armenia and Azerbaijan from September to November 2020, its parliament and government buildings were subsequently stormed by demonstrators."
Factually, what happened "from September to November 2020" was "the military hostilities between Armenia and Azerbaijan." This is the wording used by the Monitoring Committee during and after the 6-week war. When it comes to "the conflict" between them, it actually lasted from the late 1980s to 2020.