This sort of thing has happened before.
The makers of games like “World of Tanks” and “War Thunder” have had a few instances of players who work in the defense industry tell them their specs for a particular tank aren’t accurate - and then proceed to send them classified documents laying out entire systems!
The publishers report this to authorities when it happens but sometimes these idiots will be arguing with other players over details and upload this info directly to public sites where everyone can see it. It gets deleted as quickly as possible by the sites but the damage is already done.
Some people are just too stupid to be trusted with information.
“World of Tanks” is a game whose developer (Wargaming) is Russian.