It’s hard to make sense of it beyond, as you say, trying to drive a wedge between the Chinese and USSR.
My understanding is that the USSR’s main contribution to the Korean War was MIGs and pilots and various support crews, and various military advisers.
Maybe the leaflet was trying to discourage the Chinese from accepting or supporting the Soviets? But if the Chinese government and military had decided to accept and support them a few leaflets wouldn’t alter it.
Maybe it just shows the lack of thought behind, and impact of, psyops war.
As a simple example, there was an American soldier in my city in WWII who killed a few Australian women and caused great alarm for a while. http://www.enet.org.au/historyonline/brownout/brownout.htm It didn’t have the slightest effect on Australian support for American troops, in Melbourne or anywhere else. My grandparents, like many other people in Melbourne, continued to host American soldiers in their home during this period. Japanese psyops could have flogged this issue to death but it wouldn’t have had the least effect.
Then again, when pre-existing beliefs or prejudice or bigotry issues come into it, my grandparents, my father and my aunt (his sister), like just about every other Australian, all believed that the Japanese would be raping and killing if they got here (which they would have!). Psyops could have exploited that, but only because people already believed it.
I don’t think psyops has a great impact on anything to do with seriously affecting combat troops, apart from causing laughter on (a) the enemy side and (b) their own side. Admittedly, I’m basing this on the few geniuses I’ve met wearing the purple patch
of the Australian Psychology Corps (Corps - they couldn’t field a platoon before lunchtime, and then they’d all be up each other trying to find their inner selves before they got out of bed!)