The height of military tensions were in the late 50s, when China and Taiwan were shelling each other. In later decades, they still sometimes deliberately shelled each other as a statement to others that the China-Taiwan issue is a domestic Chinese issue. Nowadays neither side has unleashed a shot for well over 30 years.
The US has maintained the One China Policy for decades as well. Officially they haven't changed the policy, but unofficially they are trying to change it into a "Taiwan Independence Policy" without admitting that they are. This is where a lot of recent US-China tensions come from, especially on the military side.
Anything Russia does to other states has got absolutely nothing to do with it.