I have actually experienced this, living in a backwater country.
When corporate is incapable/incompetent to measure performance via beter means (results), they invade the privacy of their employees by spying on them.
This was fine, before Covid-19, because there was usually provisions in the contract. However, I find the same thing happening even though I'm on a VPN in to work, to connect to the workplace, while using my own Internet, WIFI, Network and computer hardware while WFH.
How do I know?
It's simple, counter-espionage. Just do things you're not expected to do and wait for the reaction, it will be subtle. Haha.